diff --git a/backend/app/api/api_v1/endpoints/settings.py b/backend/app/api/api_v1/endpoints/settings.py
index 0872a8a..404de92 100644
--- a/backend/app/api/api_v1/endpoints/settings.py
+++ b/backend/app/api/api_v1/endpoints/settings.py
@@ -23,6 +23,7 @@ from app.core.security import require_admin_auth
 from app.models.setting import Setting
 from app.services.alert_rules import evaluate_alert_rules, send_current_alerts
 from app.services.notifications import send_notification
+from app.services.summary_notifications import build_summary, send_summary_notification
 
 router = APIRouter()
 logger = logging.getLogger(__name__)
@@ -177,6 +178,48 @@ SETTING_DEFAULTS: List[Dict[str, Any]] = [
         "value_type": "integer",
         "category": "notifications",
     },
+    {
+        "key": "notifications.summary_daily_enabled",
+        "value": "false",
+        "description": "Send one daily DMARC activity summary notification",
+        "value_type": "boolean",
+        "category": "notifications",
+    },
+    {
+        "key": "notifications.summary_weekly_enabled",
+        "value": "false",
+        "description": "Send one weekly DMARC activity summary notification",
+        "value_type": "boolean",
+        "category": "notifications",
+    },
+    {
+        "key": "notifications.summary_send_hour_utc",
+        "value": "8",
+        "description": "UTC hour when scheduled summary notifications can be sent",
+        "value_type": "integer",
+        "category": "notifications",
+    },
+    {
+        "key": "notifications.summary_weekday_utc",
+        "value": "0",
+        "description": "UTC weekday for weekly summaries, where 0 is Monday",
+        "value_type": "integer",
+        "category": "notifications",
+    },
+    {
+        "key": "notifications.summary_daily_last_sent_date",
+        "value": "",
+        "description": "Internal date marker for the last sent daily summary",
+        "value_type": "string",
+        "category": "notifications",
+    },
+    {
+        "key": "notifications.summary_weekly_last_sent_week",
+        "value": "",
+        "description": "Internal ISO week marker for the last sent weekly summary",
+        "value_type": "string",
+        "category": "notifications",
+    },
 ]
 
 # Keys whose values should be redacted in GET responses (treated as secrets)
@@ -279,6 +322,19 @@ class AlertNotificationResponse(BaseModel):
     notification: Dict[str, Any]
 
 
+class SummaryResponse(BaseModel):
+    """Current DMARC summary notification preview."""
+
+    summary: Dict[str, Any]
+
+
+class SummaryNotificationResponse(BaseModel):
+    """DMARC summary plus notification delivery status."""
+
+    summary: Dict[str, Any]
+    notification: Dict[str, Any]
+
+
 # ---------------------------------------------------------------------------
 # Endpoints
 # ---------------------------------------------------------------------------
@@ -351,6 +407,48 @@ async def send_notification_alerts(
     return result
 
 
+@router.get("/notifications/summary", response_model=SummaryResponse)
+async def preview_notification_summary(
+    period: str = "daily",
+    db: Session = Depends(get_db),
+    _auth: dict = Depends(require_admin_auth),
+) -> SummaryResponse:
+    """Preview a daily or weekly DMARC summary notification."""
+    _seed_defaults(db)
+    try:
+        summary = build_summary(db, period)
+    except ValueError as exc:
+        raise HTTPException(
+            status_code=status.HTTP_400_BAD_REQUEST,
+            detail=str(exc),
+        ) from exc
+    return {"summary": summary}
+
+
+@router.post("/notifications/summary/send", response_model=SummaryNotificationResponse)
+async def send_notification_summary(
+    period: str = "daily",
+    db: Session = Depends(get_db),
+    _auth: dict = Depends(require_admin_auth),
+) -> SummaryNotificationResponse:
+    """Send a daily or weekly DMARC summary notification immediately."""
+    _seed_defaults(db)
+    try:
+        result = send_summary_notification(db, period)
+    except ValueError as exc:
+        raise HTTPException(
+            status_code=status.HTTP_400_BAD_REQUEST,
+            detail=str(exc),
+        ) from exc
+    notification = result["notification"]
+    if not notification.get("success"):
+        raise HTTPException(
+            status_code=status.HTTP_400_BAD_REQUEST,
+            detail=result,
+        )
+    return result
+
+
 @router.get("/{key:path}", response_model=SettingResponse)
 async def get_setting(
     key: str,
diff --git a/backend/app/main.py b/backend/app/main.py
index 27f9b39..658b53e 100644
--- a/backend/app/main.py
+++ b/backend/app/main.py
@@ -27,6 +27,7 @@ from app.services.imap_client import IMAPClient
 from app.services.import_history import record_import_attempt
 from app.services.report_persistence import hydrate_report_store_from_db
 from app.services.report_store import ReportStore
+from app.services.summary_notifications import send_due_scheduled_summaries
 
 # Set up logging
 logger = logging.getLogger(__name__)
@@ -180,6 +181,25 @@ def _poll_all_enabled_sources() -> list[MailSource]:
     return enabled_sources
 
 
+def _send_due_summary_notifications() -> None:
+    """Send scheduled summary notifications when their configured cadence is due."""
+    db = SessionLocal()
+    try:
+        results = send_due_scheduled_summaries(db)
+        for period, result in results.items():
+            notification = result.get("notification", {})
+            if notification.get("success"):
+                logger.info("Sent %s DMARC summary notification", period)
+            else:
+                logger.warning(
+                    "%s DMARC summary notification was not sent: %s",
+                    period.capitalize(),
+                    notification.get("message", "Unknown error"),
+                )
+    finally:
+        db.close()
+
+
 def _next_sleep_seconds(
     min_sleep: int = 60, enabled_sources: list[MailSource] | None = None
 ) -> int:
@@ -206,6 +226,7 @@ async def scheduled_imap_polling():
             logger.info("Starting scheduled IMAP polling for DMARC reports")
             try:
                 enabled_sources = _poll_all_enabled_sources()
+                _send_due_summary_notifications()
             except Exception as e:  # pylint: disable=broad-exception-caught
                 logger.error("Error in IMAP polling task: %s", str(e))
                 enabled_sources = None
diff --git a/backend/app/services/summary_notifications.py b/backend/app/services/summary_notifications.py
new file mode 100644
index 0000000..b0667df
--- /dev/null
+++ b/backend/app/services/summary_notifications.py
@@ -0,0 +1,299 @@
+"""Daily and weekly DMARC summary notification helpers."""
+
+from __future__ import annotations
+
+import logging
+from datetime import datetime, timedelta, timezone
+from typing import Any, Dict, List, Optional
+
+from sqlalchemy import case, func
+from sqlalchemy.orm import Session
+
+from app.models.domain import Domain
+from app.models.report import DMARCReport, ReportRecord
+from app.models.setting import Setting
+from app.services.alert_rules import evaluate_alert_rules
+from app.services.notifications import send_notification
+
+logger = logging.getLogger(__name__)
+
+SUMMARY_PERIODS = {
+    "daily": 1,
+    "weekly": 7,
+}
+
+
+def _truthy(value: Optional[str], default: bool = False) -> bool:
+    if value in (None, ""):
+        return default
+    return str(value).strip().lower() in {"1", "true", "yes", "on"}
+
+
+def _int_setting(value: Optional[str], default: int) -> int:
+    try:
+        return int(value or default)
+    except (TypeError, ValueError):
+        return default
+
+
+def _settings(db: Session) -> Dict[str, Optional[str]]:
+    rows = db.query(Setting).filter(Setting.category == "notifications").all()
+    return {row.key: row.value for row in rows}
+
+
+def _set_setting(db: Session, key: str, value: str) -> None:
+    row = db.query(Setting).filter(Setting.key == key).first()
+    if row is None:
+        row = Setting(
+            key=key,
+            value=value,
+            category="notifications",
+            value_type="string",
+        )
+        db.add(row)
+    else:
+        row.value = value
+    db.commit()
+
+
+def _period_days(period: str) -> int:
+    if period not in SUMMARY_PERIODS:
+        raise ValueError("Summary period must be daily or weekly.")
+    return SUMMARY_PERIODS[period]
+
+
+def _cutoff_ts(period: str, now: Optional[datetime] = None) -> int:
+    reference = now or datetime.now(timezone.utc)
+    return int((reference - timedelta(days=_period_days(period))).timestamp())
+
+
+def _recent_records_query(db: Session, cutoff_ts: int):
+    return (
+        db.query(
+            Domain.name.label("domain"),
+            ReportRecord.source_ip.label("source_ip"),
+            ReportRecord.count.label("count"),
+            ReportRecord.dkim.label("dkim"),
+            ReportRecord.spf.label("spf"),
+        )
+        .join(DMARCReport, DMARCReport.domain_id == Domain.id)
+        .join(ReportRecord, ReportRecord.report_id == DMARCReport.id)
+        .filter(DMARCReport.begin_date >= cutoff_ts)
+    )
+
+
+def _aggregate_totals(db: Session, cutoff_ts: int) -> Dict[str, int]:
+    row = (
+        db.query(
+            func.coalesce(func.sum(ReportRecord.count), 0).label("total_messages"),
+            func.coalesce(
+                func.sum(
+                    case(
+                        (
+                            (ReportRecord.dkim == "pass") | (ReportRecord.spf == "pass"),
+                            ReportRecord.count,
+                        ),
+                        else_=0,
+                    )
+                ),
+                0,
+            ).label("compliant_messages"),
+            func.coalesce(
+                func.sum(
+                    case(
+                        (
+                            (func.coalesce(ReportRecord.dkim, "fail") != "pass")
+                            & (func.coalesce(ReportRecord.spf, "fail") != "pass"),
+                            ReportRecord.count,
+                        ),
+                        else_=0,
+                    )
+                ),
+                0,
+            ).label("failed_messages"),
+        )
+        .join(DMARCReport, DMARCReport.id == ReportRecord.report_id)
+        .filter(DMARCReport.begin_date >= cutoff_ts)
+        .first()
+    )
+    if row is None:
+        return {"total_messages": 0, "compliant_messages": 0, "failed_messages": 0}
+    return {
+        "total_messages": int(row.total_messages or 0),
+        "compliant_messages": int(row.compliant_messages or 0),
+        "failed_messages": int(row.failed_messages or 0),
+    }
+
+
+def _top_domains(db: Session, cutoff_ts: int, limit: int = 5) -> List[Dict[str, Any]]:
+    rows = (
+        _recent_records_query(db, cutoff_ts)
+        .with_entities(
+            Domain.name.label("domain"),
+            func.sum(ReportRecord.count).label("message_count"),
+        )
+        .group_by(Domain.name)
+        .order_by(func.sum(ReportRecord.count).desc())
+        .limit(limit)
+        .all()
+    )
+    return [
+        {
+            "domain": row.domain,
+            "message_count": int(row.message_count or 0),
+        }
+        for row in rows
+    ]
+
+
+def _top_sources(db: Session, cutoff_ts: int, limit: int = 5) -> List[Dict[str, Any]]:
+    rows = (
+        _recent_records_query(db, cutoff_ts)
+        .with_entities(
+            ReportRecord.source_ip.label("source_ip"),
+            func.sum(ReportRecord.count).label("message_count"),
+        )
+        .group_by(ReportRecord.source_ip)
+        .order_by(func.sum(ReportRecord.count).desc())
+        .limit(limit)
+        .all()
+    )
+    return [
+        {
+            "source_ip": row.source_ip,
+            "message_count": int(row.message_count or 0),
+        }
+        for row in rows
+    ]
+
+
+def build_summary(
+    db: Session, period: str = "daily", now: Optional[datetime] = None
+) -> Dict[str, Any]:
+    """Build a daily or weekly DMARC activity summary."""
+    cutoff = _cutoff_ts(period, now)
+    totals = _aggregate_totals(db, cutoff)
+    total_messages = totals["total_messages"]
+    compliance_rate = (
+        round((totals["compliant_messages"] / total_messages) * 100, 1) if total_messages else 0.0
+    )
+    reports_processed = (
+        db.query(func.count(DMARCReport.id)).filter(DMARCReport.begin_date >= cutoff).scalar() or 0
+    )
+    return {
+        "period": period,
+        "period_days": _period_days(period),
+        "generated_at": (now or datetime.now(timezone.utc)).isoformat(),
+        "total_domains": int(db.query(func.count(Domain.id)).scalar() or 0),
+        "reports_processed": int(reports_processed),
+        "total_messages": total_messages,
+        "compliant_messages": totals["compliant_messages"],
+        "failed_messages": totals["failed_messages"],
+        "compliance_rate": compliance_rate,
+        "top_domains": _top_domains(db, cutoff),
+        "top_sources": _top_sources(db, cutoff),
+        "alerts": evaluate_alert_rules(db),
+    }
+
+
+def format_summary_body(summary: Dict[str, Any]) -> str:
+    """Format a DMARC summary as a concise notification body."""
+    period_label = summary["period"].capitalize()
+    lines = [
+        f"{period_label} DMARC summary",
+        f"Reports processed: {summary['reports_processed']}",
+        f"Messages observed: {summary['total_messages']}",
+        f"Compliance rate: {summary['compliance_rate']}%",
+        f"DMARC failures: {summary['failed_messages']}",
+        f"Active alerts: {len(summary['alerts'])}",
+    ]
+
+    if summary["top_domains"]:
+        lines.append("")
+        lines.append("Top domains:")
+        lines.extend(
+            f"- {item['domain']}: {item['message_count']} messages"
+            for item in summary["top_domains"][:5]
+        )
+
+    if summary["top_sources"]:
+        lines.append("")
+        lines.append("Top sources:")
+        lines.extend(
+            f"- {item['source_ip']}: {item['message_count']} messages"
+            for item in summary["top_sources"][:5]
+        )
+
+    if summary["alerts"]:
+        lines.append("")
+        lines.append("Alerts:")
+        lines.extend(f"- {alert['title']}: {alert['detail']}" for alert in summary["alerts"][:5])
+        if len(summary["alerts"]) > 5:
+            lines.append(f"...and {len(summary['alerts']) - 5} more alert(s).")
+
+    return "\n".join(lines)
+
+
+def send_summary_notification(db: Session, period: str = "daily") -> Dict[str, Any]:
+    """Build and send a daily or weekly summary notification."""
+    summary = build_summary(db, period)
+    title = (
+        f"DMARQ {period} summary: "
+        f"{summary['total_messages']} message(s), {len(summary['alerts'])} alert(s)"
+    )
+    result = send_notification(
+        db,
+        title=title,
+        body=format_summary_body(summary),
+    )
+    return {"summary": summary, "notification": result.to_dict()}
+
+
+def _daily_due(settings: Dict[str, Optional[str]], now: datetime) -> bool:
+    last_sent = settings.get("notifications.summary_daily_last_sent_date")
+    return last_sent != now.date().isoformat()
+
+
+def _weekly_due(settings: Dict[str, Optional[str]], now: datetime) -> bool:
+    last_sent = settings.get("notifications.summary_weekly_last_sent_week")
+    year, week, _ = now.isocalendar()
+    return last_sent != f"{year}-W{week:02d}"
+
+
+def send_due_scheduled_summaries(
+    db: Session,
+    now: Optional[datetime] = None,
+) -> Dict[str, Dict[str, Any]]:
+    """Send enabled daily and weekly summaries when their schedule is due."""
+    settings = _settings(db)
+    current_time = now or datetime.now(timezone.utc)
+    send_hour = max(
+        0, min(23, _int_setting(settings.get("notifications.summary_send_hour_utc"), 8))
+    )
+    if current_time.hour < send_hour:
+        return {}
+
+    results: Dict[str, Dict[str, Any]] = {}
+    if _truthy(settings.get("notifications.summary_daily_enabled")) and _daily_due(
+        settings, current_time
+    ):
+        results["daily"] = send_summary_notification(db, "daily")
+        if results["daily"]["notification"].get("success"):
+            _set_setting(
+                db,
+                "notifications.summary_daily_last_sent_date",
+                current_time.date().isoformat(),
+            )
+
+    weekday = max(0, min(6, _int_setting(settings.get("notifications.summary_weekday_utc"), 0)))
+    if (
+        _truthy(settings.get("notifications.summary_weekly_enabled"))
+        and current_time.weekday() == weekday
+        and _weekly_due(settings, current_time)
+    ):
+        results["weekly"] = send_summary_notification(db, "weekly")
+        if results["weekly"]["notification"].get("success"):
+            year, week, _ = current_time.isocalendar()
+            _set_setting(db, "notifications.summary_weekly_last_sent_week", f"{year}-W{week:02d}")
+
+    return results
diff --git a/backend/app/templates/settings.html b/backend/app/templates/settings.html
index eeea592..6a4931d 100644
--- a/backend/app/templates/settings.html
+++ b/backend/app/templates/settings.html
@@ -307,7 +307,92 @@
                     </template>
                 </div>
 
+                <div class="border-t border-border pt-4 space-y-4">
+                    <div>
+                        <h3 class="text-sm font-semibold">Summary Notifications</h3>
+                    </div>
+
+                    <div class="grid grid-cols-1 md:grid-cols-2 gap-4">
+                        <div class="form-control">
+                            <label class="label cursor-pointer justify-start gap-3">
+                                <input type="checkbox"
+                                    :checked="s['notifications.summary_daily_enabled'] === 'true'"
+                                    @change="s['notifications.summary_daily_enabled'] = $event.target.checked ? 'true' : 'false'"
+                                    class="checkbox checkbox-primary" />
+                                <span class="label-text font-medium">Daily summary</span>
+                            </label>
+                        </div>
+
+                        <div class="form-control">
+                            <label class="label cursor-pointer justify-start gap-3">
+                                <input type="checkbox"
+                                    :checked="s['notifications.summary_weekly_enabled'] === 'true'"
+                                    @change="s['notifications.summary_weekly_enabled'] = $event.target.checked ? 'true' : 'false'"
+                                    class="checkbox checkbox-primary" />
+                                <span class="label-text font-medium">Weekly summary</span>
+                            </label>
+                        </div>
+                    </div>
+
+                    <div class="grid grid-cols-1 md:grid-cols-3 gap-4">
+                        <div class="form-control w-full">
+                            <label class="label"><span class="label-text font-medium">Send Hour (UTC)</span></label>
+                            <input type="number" x-model.number="s['notifications.summary_send_hour_utc']"
+                                class="input input-bordered w-full" min="0" max="23" />
+                        </div>
+                        <div class="form-control w-full">
+                            <label class="label"><span class="label-text font-medium">Weekly Day</span></label>
+                            <select x-model="s['notifications.summary_weekday_utc']" class="input input-bordered w-full">
+                                <option value="0">Monday</option>
+                                <option value="1">Tuesday</option>
+                                <option value="2">Wednesday</option>
+                                <option value="3">Thursday</option>
+                                <option value="4">Friday</option>
+                                <option value="5">Saturday</option>
+                                <option value="6">Sunday</option>
+                            </select>
+                        </div>
+                        <div class="form-control w-full">
+                            <label class="label"><span class="label-text font-medium">Preview Period</span></label>
+                            <select x-model="summaryPeriod" class="input input-bordered w-full">
+                                <option value="daily">Daily</option>
+                                <option value="weekly">Weekly</option>
+                            </select>
+                        </div>
+                    </div>
+
+                    <template x-if="summaryPreview">
+                        <div class="alert alert-info">
+                            <span x-text="`${summaryPreview.total_messages} messages, ${summaryPreview.reports_processed} reports, ${summaryPreview.alerts.length} active alerts.`"></span>
+                        </div>
+                    </template>
+                </div>
+
                 <div class="flex flex-col sm:flex-row justify-end gap-2">
+                    <button type="button" class="btn btn-outline btn-md" :disabled="saving || previewingSummary" @click="previewSummary()">
+                        <template x-if="!previewingSummary">
+                            <svg xmlns="http://www.w3.org/2000/svg" width="16" height="16" viewBox="0 0 24 24" fill="none"
+                                stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" class="mr-2">
+                                <path d="M3 3v18h18"></path>
+                                <path d="M18 17V9"></path>
+                                <path d="M13 17V5"></path>
+                                <path d="M8 17v-3"></path>
+                            </svg>
+                        </template>
+                        <template x-if="previewingSummary"><span class="loading loading-spinner loading-xs mr-2"></span></template>
+                        Preview Summary
+                    </button>
+                    <button type="button" class="btn btn-outline btn-md" :disabled="saving || sendingSummary" @click="sendSummaryNow()">
+                        <template x-if="!sendingSummary">
+                            <svg xmlns="http://www.w3.org/2000/svg" width="16" height="16" viewBox="0 0 24 24" fill="none"
+                                stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" class="mr-2">
+                                <path d="M3 3v18h18"></path>
+                                <path d="m19 9-5 5-4-4-3 3"></path>
+                            </svg>
+                        </template>
+                        <template x-if="sendingSummary"><span class="loading loading-spinner loading-xs mr-2"></span></template>
+                        Send Summary Now
+                    </button>
                     <button type="button" class="btn btn-outline btn-md" :disabled="saving || checkingAlerts" @click="checkAlerts()">
                         <template x-if="!checkingAlerts">
                             <svg xmlns="http://www.w3.org/2000/svg" width="16" height="16" viewBox="0 0 24 24" fill="none"
@@ -388,6 +473,10 @@ function settingsApp() {
         checkingAlerts: false,
         sendingAlerts: false,
         alertPreview: null,
+        previewingSummary: false,
+        sendingSummary: false,
+        summaryPeriod: 'daily',
+        summaryPreview: null,
         showCfToken: false,
 
         // Session cookie is sent automatically by the browser (httpOnly, same-origin).
@@ -510,6 +599,51 @@ function settingsApp() {
             }
         },
 
+        async previewSummary() {
+            this.previewingSummary = true;
+            try {
+                await this.saveCategory('notifications');
+                const res = await fetch(`/api/v1/settings/notifications/summary?period=${this.summaryPeriod}`, {
+                    headers: this.apiHeaders(),
+                });
+                const data = await res.json().catch(() => ({}));
+                if (!res.ok) {
+                    this.showFlash('Summary preview failed: ' + (data.detail || res.statusText), false);
+                } else {
+                    this.summaryPreview = data.summary;
+                    this.showFlash('Summary preview updated.', true);
+                }
+            } catch (err) {
+                this.showFlash('Error previewing summary: ' + err.message, false);
+            } finally {
+                this.previewingSummary = false;
+            }
+        },
+
+        async sendSummaryNow() {
+            this.sendingSummary = true;
+            try {
+                await this.saveCategory('notifications');
+                const res = await fetch(`/api/v1/settings/notifications/summary/send?period=${this.summaryPeriod}`, {
+                    method: 'POST',
+                    headers: this.apiHeaders(),
+                });
+                const data = await res.json().catch(() => ({}));
+                if (!res.ok) {
+                    const detail = data.detail || {};
+                    const notification = detail.notification || {};
+                    this.showFlash('Summary send failed: ' + (notification.message || data.detail || res.statusText), false);
+                } else {
+                    this.summaryPreview = data.summary;
+                    this.showFlash('Summary notification sent.', true);
+                }
+            } catch (err) {
+                this.showFlash('Error sending summary: ' + err.message, false);
+            } finally {
+                this.sendingSummary = false;
+            }
+        },
+
         showFlash(msg, ok) {
             this.flashMsg = msg;
             this.flashOk = ok;
diff --git a/backend/app/tests/test_settings.py b/backend/app/tests/test_settings.py
index d6a3e1c..ab005fc 100644
--- a/backend/app/tests/test_settings.py
+++ b/backend/app/tests/test_settings.py
@@ -11,6 +11,7 @@ from app.models.domain import Domain
 from app.models.report import DMARCReport, ReportRecord
 from app.models.setting import Setting
 from app.services.notifications import NotificationResult
+from app.services.summary_notifications import send_due_scheduled_summaries
 
 
 def _timestamp_days_ago(days: int) -> int:
@@ -106,6 +107,10 @@ class TestSettingsAPI:
         assert "notifications.alert_compliance_drop_points" in keys
         assert "notifications.alert_failure_threshold_count" in keys
         assert "notifications.alert_missing_reports_days" in keys
+        assert "notifications.summary_daily_enabled" in keys
+        assert "notifications.summary_weekly_enabled" in keys
+        assert "notifications.summary_send_hour_utc" in keys
+        assert "notifications.summary_weekday_utc" in keys
 
     def test_list_settings_filter_by_category(self, authed_client: TestClient):
         """GET /api/v1/settings?category=dmarc returns only dmarc settings."""
@@ -410,3 +415,154 @@ class TestSettingsAPI:
         assert data["alerts"]
         assert sent_messages[0]["title"].startswith("DMARQ alert summary")
         assert "DMARC failures above threshold" in sent_messages[0]["body"]
+
+    def test_notification_summary_preview_returns_recent_activity(
+        self,
+        authed_client: TestClient,
+        db_session: Session,
+    ):
+        """GET /settings/notifications/summary returns a daily summary preview."""
+        domain = _add_domain(db_session, "summary.example")
+        _add_report_record(
+            db_session,
+            domain,
+            report_id="summary-recent",
+            days_ago=0,
+            source_ip="203.0.113.50",
+            count=25,
+        )
+        _add_report_record(
+            db_session,
+            domain,
+            report_id="summary-old",
+            days_ago=3,
+            source_ip="203.0.113.51",
+            count=99,
+        )
+        db_session.commit()
+
+        res = authed_client.get("/api/v1/settings/notifications/summary?period=daily")
+
+        assert res.status_code == 200
+        summary = res.json()["summary"]
+        assert summary["period"] == "daily"
+        assert summary["total_messages"] == 25
+        assert summary["reports_processed"] == 1
+        assert summary["top_domains"][0]["domain"] == "summary.example"
+
+    def test_notification_summary_send_uses_apprise_summary(
+        self,
+        authed_client: TestClient,
+        db_session: Session,
+        monkeypatch,
+    ):
+        """POST /settings/notifications/summary/send sends the selected summary."""
+        sent_messages = []
+
+        def fake_send_notification(
+            db, *, title, body, force=False
+        ):  # pylint: disable=unused-argument
+            sent_messages.append({"title": title, "body": body})
+            return NotificationResult(
+                success=True,
+                message="Notification sent.",
+                configured_targets=1,
+            )
+
+        monkeypatch.setattr(
+            "app.services.summary_notifications.send_notification",
+            fake_send_notification,
+        )
+
+        domain = _add_domain(db_session, "weekly.example")
+        _add_report_record(
+            db_session,
+            domain,
+            report_id="weekly-recent",
+            days_ago=2,
+            source_ip="203.0.113.60",
+            count=40,
+        )
+        db_session.commit()
+
+        res = authed_client.post("/api/v1/settings/notifications/summary/send?period=weekly")
+
+        assert res.status_code == 200
+        data = res.json()
+        assert data["notification"]["success"] is True
+        assert data["summary"]["period"] == "weekly"
+        assert sent_messages[0]["title"].startswith("DMARQ weekly summary")
+        assert "Weekly DMARC summary" in sent_messages[0]["body"]
+
+    def test_due_scheduled_summaries_send_once_per_period(
+        self,
+        db_session: Session,
+        monkeypatch,
+    ):
+        """Scheduled summaries respect enabled settings and last-sent markers."""
+        sent_messages = []
+
+        def fake_send_notification(
+            db, *, title, body, force=False
+        ):  # pylint: disable=unused-argument
+            sent_messages.append({"title": title, "body": body})
+            return NotificationResult(
+                success=True,
+                message="Notification sent.",
+                configured_targets=1,
+            )
+
+        monkeypatch.setattr(
+            "app.services.summary_notifications.send_notification",
+            fake_send_notification,
+        )
+
+        db_session.add_all(
+            [
+                Setting(
+                    key="notifications.summary_daily_enabled",
+                    value="true",
+                    category="notifications",
+                ),
+                Setting(
+                    key="notifications.summary_weekly_enabled",
+                    value="true",
+                    category="notifications",
+                ),
+                Setting(
+                    key="notifications.summary_send_hour_utc",
+                    value="8",
+                    category="notifications",
+                ),
+                Setting(
+                    key="notifications.summary_weekday_utc",
+                    value="0",
+                    category="notifications",
+                ),
+            ]
+        )
+        domain = _add_domain(db_session, "scheduled.example")
+        _add_report_record(
+            db_session,
+            domain,
+            report_id="scheduled-recent",
+            days_ago=0,
+            source_ip="203.0.113.70",
+            count=12,
+        )
+        db_session.commit()
+        now = datetime(2026, 5, 18, 8, 30, tzinfo=timezone.utc)
+
+        first = send_due_scheduled_summaries(db_session, now=now)
+        second = send_due_scheduled_summaries(db_session, now=now)
+
+        assert set(first) == {"daily", "weekly"}
+        assert second == {}
+        assert len(sent_messages) == 2
+        assert (
+            db_session.query(Setting)
+            .filter(Setting.key == "notifications.summary_daily_last_sent_date")
+            .first()
+            .value
+            == "2026-05-18"
+        )
diff --git a/docs/deployment/configuration.md b/docs/deployment/configuration.md
index bb3b6c3..9225ad7 100644
--- a/docs/deployment/configuration.md
+++ b/docs/deployment/configuration.md
@@ -92,6 +92,10 @@ from API responses.
 | `notifications.alert_failure_threshold_count` | Failed messages in the last day before alerting | `100` | `250` |
 | `notifications.alert_missing_reports_enabled` | Alert when a monitored domain stops receiving reports | `true` | `true` |
 | `notifications.alert_missing_reports_days` | Days without reports before alerting | `2` | `3` |
+| `notifications.summary_daily_enabled` | Send one daily DMARC activity summary | `false` | `true` |
+| `notifications.summary_weekly_enabled` | Send one weekly DMARC activity summary | `false` | `true` |
+| `notifications.summary_send_hour_utc` | UTC hour for scheduled summaries | `8` | `7` |
+| `notifications.summary_weekday_utc` | UTC weekday for weekly summaries, where 0 is Monday | `0` | `4` |
 
 ### Cloudflare Integration
 
diff --git a/docs/development/roadmap.md b/docs/development/roadmap.md
index 8ae726d..f9cb2bc 100644
--- a/docs/development/roadmap.md
+++ b/docs/development/roadmap.md
@@ -83,7 +83,7 @@ Follow-up:
 
 ## Later Milestones
 
-- Notifications and alert rules. Apprise delivery, test notifications, and current alert-rule evaluation are in place; scheduled summaries and alert history remain.
+- Notifications and alert rules. Apprise delivery, test notifications, alert-rule evaluation, and scheduled daily/weekly summaries are in place; alert history remains.
 - DNS health and Cloudflare read-only inspection.
 - Guided setup and operator health screens.
 - Forensic/RUF report support.
diff --git a/docs/milestones.md b/docs/milestones.md
index 9e18a63..23f55a0 100644
--- a/docs/milestones.md
+++ b/docs/milestones.md
@@ -116,9 +116,9 @@ Delivered:
 - Notification settings UI can save Apprise targets, keeps target URLs redacted after save, and can send a test notification.
 - Alert rules for new sender source, compliance drop, DMARC failures above threshold, and missing reports.
 - Notification settings UI can evaluate active alerts and send the current alert summary on demand.
+- Daily and weekly DMARC summary notifications, including scheduled delivery and manual preview/send controls.
 
 Planned:
-- Daily/weekly summary notifications.
 - Alert history.
 
 Exit criteria:
diff --git a/docs/todo.md b/docs/todo.md
index cdca81d..56b5b80 100644
--- a/docs/todo.md
+++ b/docs/todo.md
@@ -166,7 +166,7 @@ Status: Complete for the delivered reporting milestone. Alert-specific dashboard
 - [x] Add release checklist covering migrations, tests, and smoke checks
 - [x] Add Apprise notification delivery and test notification support
 - [x] Add alert rules for new sender source, compliance drop, DMARC failures above threshold, and missing reports
-- [ ] Add daily and weekly summary notifications
+- [x] Add daily and weekly summary notifications
 - [ ] Add alert history
 - [ ] DNS health guidance and Cloudflare read-only inspection
 - [ ] Guided setup and operator health pages
diff --git a/docs/user_guide/settings.md b/docs/user_guide/settings.md
index 24eaa9c..6bc7bdd 100644
--- a/docs/user_guide/settings.md
+++ b/docs/user_guide/settings.md
@@ -54,6 +54,15 @@ Set alert rules and thresholds in **Settings** > **Notifications**:
 Use **Check Alerts** to preview the current alert count, or **Send Alerts Now** to
 send the current alert summary through the configured Apprise targets.
 
+### Summary Notifications
+
+Configure daily or weekly summaries in **Settings** > **Notifications**:
+
+- **Daily Summary**: sends one summary after the configured UTC hour each day
+- **Weekly Summary**: sends one summary on the configured UTC weekday
+- **Preview Summary**: shows message volume, report count, and active alert count
+- **Send Summary Now**: sends the selected daily or weekly summary immediately
+
 ### Integration Notifications
 
 Apprise supports email, Slack, Teams, Discord, generic webhooks, and many other