diff --git a/pkg/channels/telegram/telegram.go b/pkg/channels/telegram/telegram.go
index bb04261a..d7265fb3 100644
--- a/pkg/channels/telegram/telegram.go
+++ b/pkg/channels/telegram/telegram.go
@@ -1185,7 +1185,7 @@ func (c *TelegramChannel) handleMessages(ctx context.Context, messages []*telego
 
 	inboundCtx := bus.InboundContext{
 		Channel:   c.Name(),
-		ChatID:    fmt.Sprintf("%d", chatID),
+		ChatID:    compositeChatID,
 		ChatType:  peerKind,
 		SenderID:  platformID,
 		MessageID: messageID,
diff --git a/pkg/channels/telegram/telegram_test.go b/pkg/channels/telegram/telegram_test.go
index 6d243e18..ddecad28 100644
--- a/pkg/channels/telegram/telegram_test.go
+++ b/pkg/channels/telegram/telegram_test.go
@@ -1212,8 +1212,9 @@ func TestHandleMessage_ForumTopic_SetsMetadata(t *testing.T) {
 	inbound, ok := <-messageBus.InboundChan()
 	require.True(t, ok, "expected inbound message")
 
-	// ChatID remains the parent chat; TopicID isolates the sub-conversation.
-	assert.Equal(t, "-1001234567890", inbound.ChatID)
+	// ChatID includes the thread ID for forum topics so outbound
+	// delivery resolves the correct topic without relying solely on TopicID fallback.
+	assert.Equal(t, "-1001234567890/42", inbound.ChatID)
 	assert.Equal(t, "group", inbound.Context.ChatType)
 	assert.Equal(t, "42", inbound.Context.TopicID)
 }