diff --git a/docs/channels/matrix.md b/docs/channels/matrix.md
index 6d758d3e931..a7c797e88b5 100644
--- a/docs/channels/matrix.md
+++ b/docs/channels/matrix.md
@@ -574,7 +574,7 @@ Live directory lookup uses the logged-in Matrix account:
 - `ackReactionScope`: optional ack reaction scope override (`group-mentions`, `group-all`, `direct`, `all`, `none`, `off`).
 - `reactionNotifications`: inbound reaction notification mode (`own`, `off`).
 - `mediaMaxMb`: outbound media size cap in MB.
-- `autoJoin`: invite auto-join policy (`always`, `allowlist`, `off`).
+- `autoJoin`: invite auto-join policy (`always`, `allowlist`, `off`). Default: `off`.
 - `autoJoinAllowlist`: rooms/aliases allowed when `autoJoin` is `allowlist`.
 - `dm`: DM policy block (`enabled`, `policy`, `allowFrom`).
 - `dm.allowFrom` entries should be full Matrix user IDs unless you already resolved them through live directory lookup.
diff --git a/extensions/matrix/src/channel.directory.test.ts b/extensions/matrix/src/channel.directory.test.ts
index ca87d59647e..8f79f592db8 100644
--- a/extensions/matrix/src/channel.directory.test.ts
+++ b/extensions/matrix/src/channel.directory.test.ts
@@ -258,7 +258,6 @@ describe("matrix directory", () => {
       }),
     ).toEqual([
       '- Matrix rooms: groupPolicy="open" allows any room to trigger (mention-gated). Set channels.matrix.groupPolicy="allowlist" + channels.matrix.groups (and optionally channels.matrix.groupAllowFrom) to restrict rooms.',
-      '- Matrix invites: autoJoin="always" joins any invited room before message policy applies. Set channels.matrix.autoJoin="allowlist" + channels.matrix.autoJoinAllowlist (or channels.matrix.autoJoin="off") to restrict joins.',
     ]);
 
     expect(
@@ -293,17 +292,17 @@ describe("matrix directory", () => {
       }),
     ).toEqual([
       '- Matrix rooms: groupPolicy="open" allows any room to trigger (mention-gated). Set channels.matrix.accounts.assistant.groupPolicy="allowlist" + channels.matrix.accounts.assistant.groups (and optionally channels.matrix.accounts.assistant.groupAllowFrom) to restrict rooms.',
-      '- Matrix invites: autoJoin="always" joins any invited room before message policy applies. Set channels.matrix.accounts.assistant.autoJoin="allowlist" + channels.matrix.accounts.assistant.autoJoinAllowlist (or channels.matrix.accounts.assistant.autoJoin="off") to restrict joins.',
     ]);
   });
 
-  it("reports invite auto-join warnings even when room policy is restricted", () => {
+  it("reports invite auto-join warnings only when explicitly enabled", () => {
     expect(
       matrixPlugin.security?.collectWarnings?.({
         cfg: {
           channels: {
             matrix: {
               groupPolicy: "allowlist",
+              autoJoin: "always",
             },
           },
         } as CoreConfig,
@@ -312,6 +311,7 @@ describe("matrix directory", () => {
             channels: {
               matrix: {
                 groupPolicy: "allowlist",
+                autoJoin: "always",
               },
             },
           } as CoreConfig,
diff --git a/extensions/matrix/src/channel.ts b/extensions/matrix/src/channel.ts
index 2fc7335b713..38b82469ade 100644
--- a/extensions/matrix/src/channel.ts
+++ b/extensions/matrix/src/channel.ts
@@ -165,7 +165,7 @@ export const matrixPlugin: ChannelPlugin<ResolvedMatrixAccount> = {
           `- Matrix rooms: groupPolicy="open" allows any room to trigger (mention-gated). Set ${configPath}.groupPolicy="allowlist" + ${configPath}.groups (and optionally ${configPath}.groupAllowFrom) to restrict rooms.`,
         );
       }
-      if ((account.config.autoJoin ?? "always") === "always") {
+      if ((account.config.autoJoin ?? "off") === "always") {
         warnings.push(
           `- Matrix invites: autoJoin="always" joins any invited room before message policy applies. Set ${configPath}.autoJoin="allowlist" + ${configPath}.autoJoinAllowlist (or ${configPath}.autoJoin="off") to restrict joins.`,
         );
diff --git a/extensions/matrix/src/matrix/monitor/auto-join.test.ts b/extensions/matrix/src/matrix/monitor/auto-join.test.ts
index 8cbc082ffd7..ebe36144a5e 100644
--- a/extensions/matrix/src/matrix/monitor/auto-join.test.ts
+++ b/extensions/matrix/src/matrix/monitor/auto-join.test.ts
@@ -58,6 +58,22 @@ describe("registerMatrixAutoJoin", () => {
     expect(joinRoom).toHaveBeenCalledWith("!room:example.org");
   });
 
+  it("does not auto-join invites by default", async () => {
+    const { client, getInviteHandler, joinRoom } = createClientStub();
+
+    registerMatrixAutoJoin({
+      client,
+      accountConfig: {},
+      runtime: {
+        log: vi.fn(),
+        error: vi.fn(),
+      } as unknown as import("openclaw/plugin-sdk/matrix").RuntimeEnv,
+    });
+
+    expect(getInviteHandler()).toBeNull();
+    expect(joinRoom).not.toHaveBeenCalled();
+  });
+
   it("ignores invites outside allowlist when autoJoin=allowlist", async () => {
     const { client, getInviteHandler, joinRoom, resolveRoom } = createClientStub();
     resolveRoom.mockResolvedValue(null);
diff --git a/extensions/matrix/src/matrix/monitor/auto-join.ts b/extensions/matrix/src/matrix/monitor/auto-join.ts
index 9df9d7f3b7b..4357975ad5d 100644
--- a/extensions/matrix/src/matrix/monitor/auto-join.ts
+++ b/extensions/matrix/src/matrix/monitor/auto-join.ts
@@ -16,7 +16,7 @@ export function registerMatrixAutoJoin(params: {
     }
     runtime.log?.(message);
   };
-  const autoJoin = accountConfig.autoJoin ?? "always";
+  const autoJoin = accountConfig.autoJoin ?? "off";
   const rawAllowlist = (accountConfig.autoJoinAllowlist ?? [])
     .map((entry) => String(entry).trim())
     .filter(Boolean);
diff --git a/extensions/matrix/src/types.ts b/extensions/matrix/src/types.ts
index 962fb0f3169..9f5e205a337 100644
--- a/extensions/matrix/src/types.ts
+++ b/extensions/matrix/src/types.ts
@@ -109,7 +109,7 @@ export type MatrixConfig = {
   startupVerificationCooldownHours?: number;
   /** Max outbound media size in MB. */
   mediaMaxMb?: number;
-  /** Auto-join invites (always|allowlist|off). Default: always. */
+  /** Auto-join invites (always|allowlist|off). Default: off. */
   autoJoin?: "always" | "allowlist" | "off";
   /** Allowlist for auto-join invites (room IDs, aliases). */
   autoJoinAllowlist?: Array<string | number>;