diff --git a/src/firetower/incidents/serializers.py b/src/firetower/incidents/serializers.py
index ebdfab34..0fd9d0d0 100644
--- a/src/firetower/incidents/serializers.py
+++ b/src/firetower/incidents/serializers.py
@@ -18,6 +18,7 @@
     Tag,
     TagType,
 )
+from .services import sync_incident_to_slack
 
 
 @dataclass
@@ -559,6 +560,12 @@ def update(self, instance: Incident, validated_data: dict) -> Incident:
             )
             instance.impact_type_tags.set(tags)
 
+        # Only sync to Slack if title, severity, or captain changed
+        topic_fields = {"title", "severity", "captain"}
+        sync_relevant_fields = topic_fields.intersection(validated_data.keys())
+        if sync_relevant_fields:
+            sync_incident_to_slack(instance)
+
         return instance
 
 
diff --git a/src/firetower/incidents/services.py b/src/firetower/incidents/services.py
index 378968ab..e8b7b888 100644
--- a/src/firetower/incidents/services.py
+++ b/src/firetower/incidents/services.py
@@ -5,6 +5,7 @@
 from django.conf import settings
 from django.utils import timezone
 
+from firetower.auth.models import ExternalProfileType
 from firetower.auth.services import get_or_create_user_from_slack_id
 from firetower.incidents.models import ExternalLinkType, Incident
 from firetower.integrations.services import SlackService
@@ -114,3 +115,46 @@ def sync_incident_participants_from_slack(
     )
 
     return stats
+
+
+def sync_incident_to_slack(incident: Incident) -> None:
+    """
+    Sync incident changes to Slack channel topic.
+
+    Updates the Slack channel topic with the incident's title, severity, and captain.
+    """
+    slack_link = incident.external_links.filter(type=ExternalLinkType.SLACK).first()
+
+    if not slack_link:
+        logger.warning(f"No Slack link found for incident {incident.id}")
+        return
+
+    channel_id = _slack_service.parse_channel_id_from_url(slack_link.url)
+
+    if not channel_id:
+        logger.warning(f"Could not parse channel ID from URL: {slack_link.url}")
+        return
+
+    if incident.captain:
+        slack_profile = incident.captain.external_profiles.filter(
+            type=ExternalProfileType.SLACK
+        ).first()
+        if slack_profile:
+            captain_display = f"<@{slack_profile.external_id}>"
+        else:
+            captain_display = incident.captain.get_full_name()
+    else:
+        captain_display = "None"
+
+    # Slack topic limit is 250 chars, truncate title to fit
+    prefix = f"[{incident.severity}] {incident.incident_number} "
+    suffix = f" | IC: {captain_display}"
+    max_title_len = 250 - len(prefix) - len(suffix)
+    title = incident.title[:max_title_len]
+
+    topic = f"{prefix}{title}{suffix}"
+
+    if _slack_service.update_channel_topic(channel_id, topic):
+        logger.info(f"Successfully updated topic for incident {incident.id}")
+    else:
+        logger.error(f"Failed to update topic for incident {incident.id}")
diff --git a/src/firetower/incidents/tests/test_serializers.py b/src/firetower/incidents/tests/test_serializers.py
index b4be67ba..6cd3677e 100644
--- a/src/firetower/incidents/tests/test_serializers.py
+++ b/src/firetower/incidents/tests/test_serializers.py
@@ -1,3 +1,5 @@
+from unittest.mock import patch
+
 import pytest
 from django.conf import settings
 from django.contrib.auth.models import User
@@ -14,6 +16,7 @@
 from firetower.incidents.serializers import (
     IncidentDetailUISerializer,
     IncidentListUISerializer,
+    IncidentWriteSerializer,
 )
 
 
@@ -143,3 +146,87 @@ def test_incident_detail_serialization(self):
         )
         assert "jira" not in data["external_links"]  # Not set, so not included
         assert len(data["external_links"]) == 1
+
+
+@pytest.mark.django_db
+class TestIncidentWriteSerializerSlackSync:
+    @pytest.fixture
+    def incident(self):
+        captain = User.objects.create_user(
+            username="captain@example.com",
+            email="captain@example.com",
+            first_name="Jane",
+            last_name="Captain",
+        )
+        reporter = User.objects.create_user(
+            username="reporter@example.com",
+            email="reporter@example.com",
+            first_name="John",
+            last_name="Reporter",
+        )
+        return Incident.objects.create(
+            title="Test Incident",
+            status=IncidentStatus.ACTIVE,
+            severity=IncidentSeverity.P1,
+            captain=captain,
+            reporter=reporter,
+        )
+
+    @pytest.fixture
+    def new_captain(self):
+        return User.objects.create_user(
+            username="newcaptain@example.com",
+            email="newcaptain@example.com",
+            first_name="New",
+            last_name="Captain",
+        )
+
+    @patch("firetower.incidents.serializers.sync_incident_to_slack")
+    def test_syncs_on_title_change(self, mock_sync, incident):
+        serializer = IncidentWriteSerializer(
+            incident, data={"title": "New Title"}, partial=True
+        )
+        serializer.is_valid(raise_exception=True)
+        serializer.save()
+
+        mock_sync.assert_called_once_with(incident)
+
+    @patch("firetower.incidents.serializers.sync_incident_to_slack")
+    def test_syncs_on_severity_change(self, mock_sync, incident):
+        serializer = IncidentWriteSerializer(
+            incident, data={"severity": IncidentSeverity.P2}, partial=True
+        )
+        serializer.is_valid(raise_exception=True)
+        serializer.save()
+
+        mock_sync.assert_called_once_with(incident)
+
+    @patch("firetower.incidents.serializers.sync_incident_to_slack")
+    def test_syncs_on_captain_change(self, mock_sync, incident, new_captain):
+        serializer = IncidentWriteSerializer(
+            incident, data={"captain": new_captain.email}, partial=True
+        )
+        serializer.is_valid(raise_exception=True)
+        serializer.save()
+
+        mock_sync.assert_called_once_with(incident)
+
+    @patch("firetower.incidents.serializers.sync_incident_to_slack")
+    def test_does_not_sync_on_description_change(self, mock_sync, incident):
+        serializer = IncidentWriteSerializer(
+            incident, data={"description": "Updated description"}, partial=True
+        )
+        serializer.is_valid(raise_exception=True)
+        serializer.save()
+
+        mock_sync.assert_not_called()
+
+    @patch("firetower.incidents.serializers.sync_incident_to_slack")
+    def test_does_not_sync_on_status_change(self, mock_sync, incident):
+        serializer = IncidentWriteSerializer(
+            incident, data={"status": IncidentStatus.MITIGATED}, partial=True
+        )
+        serializer.is_valid(raise_exception=True)
+        serializer.save()
+
+        mock_sync.assert_not_called()
diff --git a/src/firetower/incidents/tests/test_services.py b/src/firetower/incidents/tests/test_services.py
index 34f50114..6cb7127a 100644
--- a/src/firetower/incidents/tests/test_services.py
+++ b/src/firetower/incidents/tests/test_services.py
@@ -13,7 +13,10 @@
     IncidentSeverity,
     IncidentStatus,
 )
-from firetower.incidents.services import sync_incident_participants_from_slack
+from firetower.incidents.services import (
+    sync_incident_participants_from_slack,
+    sync_incident_to_slack,
+)
 
 
 @pytest.mark.django_db
@@ -359,3 +362,142 @@ def test_skips_bots(self):
                     mock_get_user.assert_called_once_with("U11111")
                     assert stats.added == 1
                     assert stats.errors == []
+
+
+@pytest.mark.django_db
+class TestSyncIncidentToSlack:
+    def test_syncs_topic_to_slack_channel_with_slack_profile(self):
+        incident = Incident.objects.create(
+            title="Test Incident",
+            status=IncidentStatus.ACTIVE,
+            severity=IncidentSeverity.P1,
+        )
+        captain = User.objects.create_user(
+            username="captain@example.com",
+            email="captain@example.com",
+            first_name="Captain",
+            last_name="One",
+        )
+        ExternalProfile.objects.create(
+            user=captain,
+            type=ExternalProfileType.SLACK,
+            external_id="U99999",
+        )
+        incident.captain = captain
+        ExternalLink.objects.create(
+            incident=incident,
+            type=ExternalLinkType.SLACK,
+            url="https://workspace.slack.com/archives/C12345",
+        )
+
+        with patch(
+            "firetower.incidents.services._slack_service.update_channel_topic"
+        ) as mock_update:
+            mock_update.return_value = True
+            sync_incident_to_slack(incident)
+
+            mock_update.assert_called_once_with(
+                "C12345",
+                f"[P1] {incident.incident_number} Test Incident | IC: <@U99999>",
+            )
+
+    def test_syncs_topic_falls_back_to_full_name_without_slack_profile(self):
+        incident = Incident.objects.create(
+            title="Test Incident",
+            status=IncidentStatus.ACTIVE,
+            severity=IncidentSeverity.P1,
+        )
+        captain = User.objects.create_user(
+            username="captain@example.com",
+            email="captain@example.com",
+            first_name="Captain",
+            last_name="One",
+        )
+        incident.captain = captain
+        ExternalLink.objects.create(
+            incident=incident,
+            type=ExternalLinkType.SLACK,
+            url="https://workspace.slack.com/archives/C12345",
+        )
+
+        with patch(
+            "firetower.incidents.services._slack_service.update_channel_topic"
+        ) as mock_update:
+            mock_update.return_value = True
+            sync_incident_to_slack(incident)
+
+            mock_update.assert_called_once_with(
+                "C12345",
+                f"[P1] {incident.incident_number} Test Incident | IC: Captain One",
+            )
+
+    def test_skips_if_no_slack_link(self):
+        incident = Incident.objects.create(
+            title="Test Incident",
+            status=IncidentStatus.ACTIVE,
+            severity=IncidentSeverity.P1,
+        )
+        captain = User.objects.create_user(
+            username="captain@example.com",
+            email="captain@example.com",
+            first_name="Captain",
+            last_name="One",
+        )
+        incident.captain = captain
+
+        with patch(
+            "firetower.incidents.services._slack_service.update_channel_topic"
+        ) as mock_update:
+            sync_incident_to_slack(incident)
+            mock_update.assert_not_called()
+
+    def test_handles_invalid_channel_url(self):
+        incident = Incident.objects.create(
+            title="Test Incident",
+            status=IncidentStatus.ACTIVE,
+            severity=IncidentSeverity.P1,
+        )
+        captain = User.objects.create_user(
+            username="captain@example.com",
+            email="captain@example.com",
+            first_name="Captain",
+            last_name="One",
+        )
+        incident.captain = captain
+        ExternalLink.objects.create(
+            incident=incident,
+            type=ExternalLinkType.SLACK,
+            url="https://invalid-url.com",
+        )
+
+        with patch(
+            "firetower.incidents.services._slack_service.update_channel_topic"
+        ) as mock_update:
+            sync_incident_to_slack(incident)
+            mock_update.assert_not_called()
+
+    def test_handles_slack_api_failure(self):
+        incident = Incident.objects.create(
+            title="Test Incident",
+            status=IncidentStatus.ACTIVE,
+            severity=IncidentSeverity.P1,
+        )
+        captain = User.objects.create_user(
+            username="captain@example.com",
+            email="captain@example.com",
+            first_name="Captain",
+            last_name="One",
+        )
+        incident.captain = captain
+        ExternalLink.objects.create(
+            incident=incident,
+            type=ExternalLinkType.SLACK,
+            url="https://workspace.slack.com/archives/C12345",
+        )
+
+        with patch(
+            "firetower.incidents.services._slack_service.update_channel_topic"
+        ) as mock_update:
+            mock_update.return_value = False
+
+            sync_incident_to_slack(incident)
diff --git a/src/firetower/integrations/services/slack.py b/src/firetower/integrations/services/slack.py
index b9e8cf77..b0643f69 100644
--- a/src/firetower/integrations/services/slack.py
+++ b/src/firetower/integrations/services/slack.py
@@ -197,3 +197,30 @@ def get_user_info(self, slack_user_id: str) -> dict | None:
                 extra={"slack_user_id": slack_user_id},
             )
             return None
+
+    def update_channel_topic(self, channel_id: str, topic: str) -> bool:
+        """
+        Update Slack channel topic.
+
+        Args:
+            channel_id: Slack channel ID (e.g., C12345678)
+            topic: New topic string
+
+        Returns:
+            True if successful, False otherwise
+        """
+        if not self.client:
+            logger.warning("Cannot update channel topic - Slack client not initialized")
+            return False
+
+        try:
+            self.client.conversations_setTopic(channel=channel_id, topic=topic)
+            logger.info(f"Successfully updated topic for channel {channel_id}")
+            return True
+
+        except SlackApiError as e:
+            logger.error(
+                f"Error updating channel topic: {e.response['error']}",
+                extra={"channel_id": channel_id},
+            )
+            return False