diff --git a/CHANGELOG.md b/CHANGELOG.md
index 870b919331f..858d235c93e 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -237,6 +237,7 @@ Docs: https://docs.openclaw.ai
 ### Fixes
 
 - Slack/Identity: thread agent outbound identity (`chat:write.customize` overrides) through the channel reply delivery path so per-agent username, icon URL, and icon emoji are applied to all Slack replies including media messages. (#27134) Thanks @hou-rong.
+- Slack/Threading: resolve `replyToMode` per incoming message using chat-type-aware account config (`replyToModeByChatType` and legacy `dm.replyToMode`) so DM/channel reply threading honors overrides instead of always using monitor startup defaults. (#24717) Thanks @dbachelder.
 - Agents/Subagents delivery: refactor subagent completion announce dispatch into an explicit queue/direct/fallback state machine, recover outbound channel-plugin resolution in cold/stale plugin-registry states across announce/message/gateway send paths, finalize cleanup bookkeeping when announce flow rejects, and treat Telegram sends without `message_id` as delivery failures (instead of false-success `"unknown"` IDs). (#26867, #25961, #26803, #25069, #26741) Thanks @SmithLabsLLC and @docaohieu2808.
 - Telegram/Webhook: pre-initialize webhook bots, switch webhook processing to callback-mode JSON handling, and preserve full near-limit payload reads under delayed handlers to prevent webhook request hangs and dropped updates. (#26156)
 - Slack/Session threads: prevent oversized parent-session inheritance from silently bricking new thread sessions, surface embedded context-overflow empty-result failures to users, and add configurable `session.parentForkMaxTokens` (default `100000`, `0` disables). (#26912) Thanks @markshields-tl.
diff --git a/src/slack/monitor/message-handler/dispatch.ts b/src/slack/monitor/message-handler/dispatch.ts
index b987585a254..a7a852ea14b 100644
--- a/src/slack/monitor/message-handler/dispatch.ts
+++ b/src/slack/monitor/message-handler/dispatch.ts
@@ -101,7 +101,7 @@ export async function dispatchPreparedSlackMessage(prepared: PreparedSlackMessag
 
   const { statusThreadTs, isThreadReply } = resolveSlackThreadTargets({
     message,
-    replyToMode: ctx.replyToMode,
+    replyToMode: prepared.replyToMode,
   });
 
   const messageTs = message.ts ?? message.event_ts;
@@ -112,7 +112,7 @@ export async function dispatchPreparedSlackMessage(prepared: PreparedSlackMessag
   // mark this to ensure only the first reply is threaded.
   const hasRepliedRef = { value: false };
   const replyPlan = createSlackReplyDeliveryPlan({
-    replyToMode: ctx.replyToMode,
+    replyToMode: prepared.replyToMode,
     incomingThreadTs,
     messageTs,
     hasRepliedRef,
@@ -178,7 +178,7 @@ export async function dispatchPreparedSlackMessage(prepared: PreparedSlackMessag
     nativeStreaming: slackStreaming.nativeStreaming,
   });
   const streamThreadHint = resolveSlackStreamingThreadHint({
-    replyToMode: ctx.replyToMode,
+    replyToMode: prepared.replyToMode,
     incomingThreadTs,
     messageTs,
     isThreadReply,
@@ -200,7 +200,7 @@ export async function dispatchPreparedSlackMessage(prepared: PreparedSlackMessag
       runtime,
       textLimit: ctx.textLimit,
       replyThreadTs,
-      replyToMode: ctx.replyToMode,
+      replyToMode: prepared.replyToMode,
       ...(slackIdentity ? { identity: slackIdentity } : {}),
     });
     replyPlan.markSent();
diff --git a/src/slack/monitor/message-handler/prepare.test.ts b/src/slack/monitor/message-handler/prepare.test.ts
index 548e2b0b471..1be530ee039 100644
--- a/src/slack/monitor/message-handler/prepare.test.ts
+++ b/src/slack/monitor/message-handler/prepare.test.ts
@@ -120,6 +120,9 @@ describe("slack prepareSlackMessage inbound contract", () => {
       botTokenSource: "config",
       appTokenSource: "config",
       config,
+      replyToMode: config.replyToMode,
+      replyToModeByChatType: config.replyToModeByChatType,
+      dm: config.dm,
     };
   }
 
@@ -166,6 +169,7 @@ describe("slack prepareSlackMessage inbound contract", () => {
         replyToMode: "all",
         thread: { initialHistoryLimit: 20 },
       },
+      replyToMode: "all",
     };
   }
 
@@ -473,6 +477,71 @@ describe("slack prepareSlackMessage inbound contract", () => {
     expect(prepared!.ctxPayload.MessageThreadId).toBe("1.000");
   });
 
+  it("respects replyToModeByChatType.direct override for DMs", async () => {
+    const slackCtx = createInboundSlackCtx({
+      cfg: {
+        channels: { slack: { enabled: true, replyToMode: "all" } },
+      } as OpenClawConfig,
+      replyToMode: "all",
+    });
+    // oxlint-disable-next-line typescript/no-explicit-any
+    slackCtx.resolveUserName = async () => ({ name: "Alice" }) as any;
+
+    const prepared = await prepareMessageWith(
+      slackCtx,
+      createSlackAccount({ replyToMode: "all", replyToModeByChatType: { direct: "off" } }),
+      createSlackMessage({}), // DM (channel_type: "im")
+    );
+
+    expect(prepared).toBeTruthy();
+    expect(prepared!.replyToMode).toBe("off");
+    expect(prepared!.ctxPayload.MessageThreadId).toBeUndefined();
+  });
+
+  it("still threads channel messages when replyToModeByChatType.direct is off", async () => {
+    const slackCtx = createInboundSlackCtx({
+      cfg: {
+        channels: { slack: { enabled: true, replyToMode: "all", groupPolicy: "open" } },
+      } as OpenClawConfig,
+      replyToMode: "all",
+      defaultRequireMention: false,
+    });
+    // oxlint-disable-next-line typescript/no-explicit-any
+    slackCtx.resolveUserName = async () => ({ name: "Alice" }) as any;
+    slackCtx.resolveChannelName = async () => ({ name: "general", type: "channel" });
+
+    const prepared = await prepareMessageWith(
+      slackCtx,
+      createSlackAccount({ replyToMode: "all", replyToModeByChatType: { direct: "off" } }),
+      createSlackMessage({ channel: "C123", channel_type: "channel" }),
+    );
+
+    expect(prepared).toBeTruthy();
+    expect(prepared!.replyToMode).toBe("all");
+    expect(prepared!.ctxPayload.MessageThreadId).toBe("1.000");
+  });
+
+  it("respects dm.replyToMode legacy override for DMs", async () => {
+    const slackCtx = createInboundSlackCtx({
+      cfg: {
+        channels: { slack: { enabled: true, replyToMode: "all" } },
+      } as OpenClawConfig,
+      replyToMode: "all",
+    });
+    // oxlint-disable-next-line typescript/no-explicit-any
+    slackCtx.resolveUserName = async () => ({ name: "Alice" }) as any;
+
+    const prepared = await prepareMessageWith(
+      slackCtx,
+      createSlackAccount({ replyToMode: "all", dm: { replyToMode: "off" } }),
+      createSlackMessage({}), // DM
+    );
+
+    expect(prepared).toBeTruthy();
+    expect(prepared!.replyToMode).toBe("off");
+    expect(prepared!.ctxPayload.MessageThreadId).toBeUndefined();
+  });
+
   it("marks first thread turn and injects thread history for a new thread session", async () => {
     const { storePath } = makeTmpStorePath();
     const replies = vi
@@ -671,7 +740,7 @@ describe("prepareSlackMessage sender prefix", () => {
   async function prepareSenderPrefixMessage(ctx: SlackMonitorContext, text: string, ts: string) {
     return prepareSlackMessage({
       ctx,
-      account: { accountId: "default", config: {} } as never,
+      account: { accountId: "default", config: {}, replyToMode: "off" } as never,
       message: {
         type: "message",
         channel: "C1",
diff --git a/src/slack/monitor/message-handler/prepare.ts b/src/slack/monitor/message-handler/prepare.ts
index 02ee265f7ca..9462ac7676e 100644
--- a/src/slack/monitor/message-handler/prepare.ts
+++ b/src/slack/monitor/message-handler/prepare.ts
@@ -29,7 +29,7 @@ import { logVerbose, shouldLogVerbose } from "../../../globals.js";
 import { enqueueSystemEvent } from "../../../infra/system-events.js";
 import { resolveAgentRoute } from "../../../routing/resolve-route.js";
 import { resolveThreadSessionKeys } from "../../../routing/session-key.js";
-import type { ResolvedSlackAccount } from "../../accounts.js";
+import { resolveSlackReplyToMode, type ResolvedSlackAccount } from "../../accounts.js";
 import { reactSlackMessage } from "../../actions.js";
 import { sendMessageSlack } from "../../send.js";
 import { resolveSlackThreadContext } from "../../threading.js";
@@ -175,7 +175,9 @@ export async function prepareSlackMessage(params: {
   });
 
   const baseSessionKey = route.sessionKey;
-  const threadContext = resolveSlackThreadContext({ message, replyToMode: ctx.replyToMode });
+  const chatType = isDirectMessage ? "direct" : isGroupDm ? "group" : "channel";
+  const replyToMode = resolveSlackReplyToMode(account, chatType);
+  const threadContext = resolveSlackThreadContext({ message, replyToMode });
   const threadTs = threadContext.incomingThreadTs;
   const isThreadReply = threadContext.isThreadReply;
   const threadKeys = resolveThreadSessionKeys({
@@ -666,6 +668,7 @@ export async function prepareSlackMessage(params: {
     channelConfig,
     replyTarget,
     ctxPayload,
+    replyToMode,
     isDirectMessage,
     isRoomish,
     historyKey,
diff --git a/src/slack/monitor/message-handler/types.ts b/src/slack/monitor/message-handler/types.ts
index 8fbf4a939dd..c99380d8b20 100644
--- a/src/slack/monitor/message-handler/types.ts
+++ b/src/slack/monitor/message-handler/types.ts
@@ -13,6 +13,7 @@ export type PreparedSlackMessage = {
   channelConfig: SlackChannelConfigResolved | null;
   replyTarget: string;
   ctxPayload: FinalizedMsgContext;
+  replyToMode: "off" | "first" | "all";
   isDirectMessage: boolean;
   isRoomish: boolean;
   historyKey: string;