diff --git a/api/v1beta2/alert_types.go b/api/v1beta2/alert_types.go
index b6531cf11..3a9e2f7c3 100644
--- a/api/v1beta2/alert_types.go
+++ b/api/v1beta2/alert_types.go
@@ -50,6 +50,13 @@ type AlertSpec struct {
 	// +optional
 	InclusionList []string `json:"inclusionList,omitempty"`
 
+	// EventMetadata is an optional field for adding metadata to events emitted by the
+	// controller. Metadata fields added by the controller have priority over the fields
+	// added here, and the fields added here have priority over fields originally present
+	// in the event.
+	// +optional
+	EventMetadata map[string]string `json:"eventMetadata,omitempty"`
+
 	// ExclusionList specifies a list of Golang regular expressions
 	// to be used for excluding messages.
 	// +optional
diff --git a/api/v1beta2/zz_generated.deepcopy.go b/api/v1beta2/zz_generated.deepcopy.go
index cdbd33f57..78dd00068 100644
--- a/api/v1beta2/zz_generated.deepcopy.go
+++ b/api/v1beta2/zz_generated.deepcopy.go
@@ -103,6 +103,13 @@ func (in *AlertSpec) DeepCopyInto(out *AlertSpec) {
 		*out = make([]string, len(*in))
 		copy(*out, *in)
 	}
+	if in.EventMetadata != nil {
+		in, out := &in.EventMetadata, &out.EventMetadata
+		*out = make(map[string]string, len(*in))
+		for key, val := range *in {
+			(*out)[key] = val
+		}
+	}
 	if in.ExclusionList != nil {
 		in, out := &in.ExclusionList, &out.ExclusionList
 		*out = make([]string, len(*in))
diff --git a/config/crd/bases/notification.toolkit.fluxcd.io_alerts.yaml b/config/crd/bases/notification.toolkit.fluxcd.io_alerts.yaml
index 23b9142b4..121e6ddd1 100644
--- a/config/crd/bases/notification.toolkit.fluxcd.io_alerts.yaml
+++ b/config/crd/bases/notification.toolkit.fluxcd.io_alerts.yaml
@@ -240,6 +240,14 @@ spec:
             description: AlertSpec defines an alerting rule for events involving a
               list of objects.
             properties:
+              eventMetadata:
+                additionalProperties:
+                  type: string
+                description: EventMetadata is an optional field for adding metadata
+                  to events emitted by the controller. Metadata fields added by the
+                  controller have priority over the fields added here, and the fields
+                  added here have priority over fields originally present in the event.
+                type: object
               eventSeverity:
                 default: info
                 description: EventSeverity specifies how to filter events based on
diff --git a/docs/api/v1beta2/notification.md b/docs/api/v1beta2/notification.md
index 0672eaf27..d097025a5 100644
--- a/docs/api/v1beta2/notification.md
+++ b/docs/api/v1beta2/notification.md
@@ -127,6 +127,21 @@ to be used for including messages.</p>
 </tr>
 <tr>
 <td>
+<code>eventMetadata</code><br>
+<em>
+map[string]string
+</em>
+</td>
+<td>
+<em>(Optional)</em>
+<p>EventMetadata is an optional field for adding metadata to events emitted by the
+controller. Metadata fields added by the controller have priority over the fields
+added here, and the fields added here have priority over fields originally present
+in the event.</p>
+</td>
+</tr>
+<tr>
+<td>
 <code>exclusionList</code><br>
 <em>
 []string
@@ -615,6 +630,21 @@ to be used for including messages.</p>
 </tr>
 <tr>
 <td>
+<code>eventMetadata</code><br>
+<em>
+map[string]string
+</em>
+</td>
+<td>
+<em>(Optional)</em>
+<p>EventMetadata is an optional field for adding metadata to events emitted by the
+controller. Metadata fields added by the controller have priority over the fields
+added here, and the fields added here have priority over fields originally present
+in the event.</p>
+</td>
+</tr>
+<tr>
+<td>
 <code>exclusionList</code><br>
 <em>
 []string
diff --git a/docs/spec/v1beta2/alerts.md b/docs/spec/v1beta2/alerts.md
index cb4c32927..c06af0729 100644
--- a/docs/spec/v1beta2/alerts.md
+++ b/docs/spec/v1beta2/alerts.md
@@ -162,6 +162,13 @@ starting the controller with the `--no-cross-namespace-refs=true` flag.
 When this flag is set, alerts can only refer to event sources in the same namespace as the alert object,
 preventing tenants from subscribing to another tenant's events.
 
+### Event metadata
+
+`.spec.eventMetadata` is an optional field for adding metadata to events emitted by the
+controller. Metadata fields added by the controller have priority over the fields
+added here, and the fields added here have priority over fields originally present
+in the event.
+
 ### Event severity
 
 `.spec.eventSeverity` is an optional field to filter events based on severity. When not specified, or
diff --git a/internal/server/event_handlers.go b/internal/server/event_handlers.go
index 5e7a4ce51..b239a8e57 100644
--- a/internal/server/event_handlers.go
+++ b/internal/server/event_handlers.go
@@ -273,14 +273,18 @@ func (s *EventServer) handleEvent() func(w http.ResponseWriter, r *http.Request)
 			}
 
 			notification := *event.DeepCopy()
+			meta := notification.Metadata
+			if meta == nil {
+				meta = make(map[string]string)
+			}
+			for key, value := range alert.Spec.EventMetadata {
+				meta[key] = value
+			}
 			if alert.Spec.Summary != "" {
-				if notification.Metadata == nil {
-					notification.Metadata = map[string]string{
-						"summary": alert.Spec.Summary,
-					}
-				} else {
-					notification.Metadata["summary"] = alert.Spec.Summary
-				}
+				meta["summary"] = alert.Spec.Summary
+			}
+			if len(meta) > 0 {
+				notification.Metadata = meta
 			}
 
 			go func(n notifier.Interface, e eventv1.Event) {