diff --git a/config/config.go b/config/config.go
index 5bed42d45e..ffceabcea4 100644
--- a/config/config.go
+++ b/config/config.go
@@ -100,6 +100,7 @@ type Config struct {
 
 		SigningSecret       string `password:"true" info:"Signing secret to verify requests from slack."`
 		InteractiveMessages bool   `info:"Enable interactive messages (e.g. buttons)."`
+		DisableBroadcastThreadReplies bool `info:"Disable broadcasting alert status updates in threads to the main channel." public:"true"`
 	}
 
 	Twilio struct {
diff --git a/graphql2/mapconfig.go b/graphql2/mapconfig.go
index f53c8bd316..c6b1cd4a06 100644
--- a/graphql2/mapconfig.go
+++ b/graphql2/mapconfig.go
@@ -68,6 +68,7 @@ func MapConfigValues(cfg config.Config) []ConfigValue {
 		{ID: "Slack.AccessToken", Type: ConfigTypeString, Description: "Slack app bot user OAuth access token (should start with xoxb-).", Value: cfg.Slack.AccessToken, Password: true},
 		{ID: "Slack.SigningSecret", Type: ConfigTypeString, Description: "Signing secret to verify requests from slack.", Value: cfg.Slack.SigningSecret, Password: true},
 		{ID: "Slack.InteractiveMessages", Type: ConfigTypeBoolean, Description: "Enable interactive messages (e.g. buttons).", Value: fmt.Sprintf("%t", cfg.Slack.InteractiveMessages)},
+		{ID: "Slack.DisableBroadcastThreadReplies", Type: ConfigTypeBoolean, Description: "Disable broadcasting alert status updates in threads to the main channel.", Value: fmt.Sprintf("%t", cfg.Slack.DisableBroadcastThreadReplies)},
 		{ID: "Twilio.Enable", Type: ConfigTypeBoolean, Description: "Enables sending and processing of Voice and SMS messages through the Twilio notification provider.", Value: fmt.Sprintf("%t", cfg.Twilio.Enable)},
 		{ID: "Twilio.VoiceName", Type: ConfigTypeString, Description: "The Twilio voice to use for Text To Speech for phone calls. See https://www.twilio.com/docs/voice/twiml/say/text-speech#polly-standard-and-neural-voices", Value: cfg.Twilio.VoiceName},
 		{ID: "Twilio.VoiceLanguage", Type: ConfigTypeString, Description: "The Twilio voice language to use for Text To Speech for phone calls. See https://www.twilio.com/docs/voice/twiml/say/text-speech#polly-standard-and-neural-voices", Value: cfg.Twilio.VoiceLanguage},
@@ -117,6 +118,7 @@ func MapPublicConfigValues(cfg config.Config) []ConfigValue {
 		{ID: "OIDC.Enable", Type: ConfigTypeBoolean, Description: "Enable OpenID Connect authentication.", Value: fmt.Sprintf("%t", cfg.OIDC.Enable)},
 		{ID: "Mailgun.Enable", Type: ConfigTypeBoolean, Description: "", Value: fmt.Sprintf("%t", cfg.Mailgun.Enable)},
 		{ID: "Slack.Enable", Type: ConfigTypeBoolean, Description: "", Value: fmt.Sprintf("%t", cfg.Slack.Enable)},
+		{ID: "Slack.DisableBroadcastThreadReplies", Type: ConfigTypeBoolean, Description: "Disable broadcasting alert status updates in threads to the main channel.", Value: fmt.Sprintf("%t", cfg.Slack.DisableBroadcastThreadReplies)},
 		{ID: "Twilio.Enable", Type: ConfigTypeBoolean, Description: "Enables sending and processing of Voice and SMS messages through the Twilio notification provider.", Value: fmt.Sprintf("%t", cfg.Twilio.Enable)},
 		{ID: "Twilio.FromNumber", Type: ConfigTypeString, Description: "The Twilio number to use for outgoing notifications.", Value: cfg.Twilio.FromNumber},
 		{ID: "Twilio.MessagingServiceSID", Type: ConfigTypeString, Description: "If set, replaces the use of From Number for SMS notifications.", Value: cfg.Twilio.MessagingServiceSID},
@@ -313,6 +315,12 @@ func ApplyConfigValues(cfg config.Config, vals []ConfigValueInput) (config.Confi
 				return cfg, err
 			}
 			cfg.Slack.InteractiveMessages = val
+		case "Slack.DisableBroadcastThreadReplies":
+			val, err := parseBool(v.ID, v.Value)
+			if err != nil {
+				return cfg, err
+			}
+			cfg.Slack.DisableBroadcastThreadReplies = val
 		case "Twilio.Enable":
 			val, err := parseBool(v.ID, v.Value)
 			if err != nil {
diff --git a/notification/slack/channel.go b/notification/slack/channel.go
index fadc8259e7..c2f33ed892 100644
--- a/notification/slack/channel.go
+++ b/notification/slack/channel.go
@@ -457,11 +457,17 @@ func (s *ChannelSender) SendMessage(ctx context.Context, msg notification.Messag
 			channelID, ts = chanTS(channelID, t.OriginalStatus.ProviderMessageID.ExternalID)
 
 			// Reply in thread if we already sent a message for this alert.
-			opts = append(opts,
+			threadOpts := []slack.MsgOption{
 				slack.MsgOptionTS(ts),
-				slack.MsgOptionBroadcast(),
 				slack.MsgOptionText(alertLink(ctx, t.AlertID, t.Summary), false),
-			)
+			}
+
+			// Conditionally add broadcast based on config (default: enabled)
+			if !cfg.Slack.DisableBroadcastThreadReplies {
+				threadOpts = append(threadOpts, slack.MsgOptionBroadcast())
+			}
+
+			opts = append(opts, threadOpts...)
 			break
 		}
 
diff --git a/test/smoke/slacknotification_test.go b/test/smoke/slacknotification_test.go
index 540c64a272..6c3721bfa0 100644
--- a/test/smoke/slacknotification_test.go
+++ b/test/smoke/slacknotification_test.go
@@ -42,3 +42,41 @@ func TestSlackNotification(t *testing.T) {
 	// should broadcast reply to channel
 	msg.ExpectBroadcastReply("Alert #1")
 }
+
+// TestSlackNotification_NoBroadcast tests that thread replies don't broadcast when disabled.
+func TestSlackNotification_NoBroadcast(t *testing.T) {
+	t.Parallel()
+
+	sql := `
+	insert into escalation_policies (id, name, repeat)
+	values
+		({{uuid "eid"}}, 'esc policy', 1);
+	insert into escalation_policy_steps (id, escalation_policy_id, delay)
+	values
+		({{uuid "esid"}}, {{uuid "eid"}}, 30);
+
+	insert into notification_channels (id, type, name, value)
+	values
+		({{uuid "chan"}}, 'SLACK', '#test', {{slackChannelID "test"}});
+
+	insert into escalation_policy_actions (escalation_policy_step_id, channel_id)
+	values
+		({{uuid "esid"}}, {{uuid "chan"}});
+
+	insert into services (id, escalation_policy_id, name)
+	values
+		({{uuid "sid"}}, {{uuid "eid"}}, 'service');
+	`
+	h := harness.NewHarness(t, sql, "slack-user-link")
+	defer h.Close()
+
+	// Disable broadcast
+	h.SetConfigValue("Slack.DisableBroadcastThreadReplies", "true")
+
+	h.CreateAlert(h.UUID("sid"), "testing")
+	msg := h.Slack().Channel("test").ExpectMessage("testing")
+
+	h.FastForward(time.Hour)
+	// Should reply in thread WITHOUT broadcast
+	msg.ExpectThreadReply("Alert #1")
+}
diff --git a/web/src/schema.d.ts b/web/src/schema.d.ts
index 9699d529d7..38972ffedd 100644
--- a/web/src/schema.d.ts
+++ b/web/src/schema.d.ts
@@ -1657,6 +1657,7 @@ type ConfigID =
   | 'Slack.AccessToken'
   | 'Slack.SigningSecret'
   | 'Slack.InteractiveMessages'
+  | 'Slack.DisableBroadcastThreadReplies'
   | 'Twilio.Enable'
   | 'Twilio.VoiceName'
   | 'Twilio.VoiceLanguage'