diff --git a/scripts/e2e/lib/bundled-plugin-install-uninstall/runtime-smoke.mjs b/scripts/e2e/lib/bundled-plugin-install-uninstall/runtime-smoke.mjs
index 329c8bfc56ae..6e53a2d10a04 100644
--- a/scripts/e2e/lib/bundled-plugin-install-uninstall/runtime-smoke.mjs
+++ b/scripts/e2e/lib/bundled-plugin-install-uninstall/runtime-smoke.mjs
@@ -641,8 +641,16 @@ function processTreeIsAlive(child) {
   }
 }
 
-function signalChildProcessTree(child, signal) {
-  if (process.platform !== "win32" && typeof child.pid === "number") {
+function defaultRunTaskkill(command, args, options) {
+  return childProcess.spawnSync(command, args, options);
+}
+
+export function signalChildProcessTree(
+  child,
+  signal,
+  { platform = process.platform, runTaskkill = defaultRunTaskkill } = {},
+) {
+  if (platform !== "win32" && typeof child.pid === "number") {
     try {
       process.kill(-child.pid, signal);
       return;
@@ -651,6 +659,16 @@ function signalChildProcessTree(child, signal) {
       // the legacy direct-child kill path as the fallback.
     }
   }
+  if (platform === "win32" && typeof child.pid === "number") {
+    const args = ["/PID", String(child.pid), "/T"];
+    if (signal === "SIGKILL") {
+      args.push("/F");
+    }
+    const result = runTaskkill("taskkill", args, { stdio: "ignore" });
+    if (!result?.error && result?.status === 0) {
+      return;
+    }
+  }
   try {
     child.kill(signal);
   } catch (error) {
diff --git a/test/scripts/bundled-plugin-install-uninstall-probe.test.ts b/test/scripts/bundled-plugin-install-uninstall-probe.test.ts
index 3dcee832f085..72c9a559d552 100644
--- a/test/scripts/bundled-plugin-install-uninstall-probe.test.ts
+++ b/test/scripts/bundled-plugin-install-uninstall-probe.test.ts
@@ -456,6 +456,32 @@ describe("bundled plugin install/uninstall probe", () => {
     expect(child.kill).not.toHaveBeenCalled();
   });
 
+  it("signals Windows runtime child process trees with taskkill", async () => {
+    const runtimeSmoke = await import(pathToFileURL(runtimeSmokePath).href);
+    const child = {
+      kill: vi.fn(),
+      pid: 12345,
+    };
+    const runTaskkill = vi.fn(() => ({ error: undefined, status: 0 }));
+
+    runtimeSmoke.signalChildProcessTree(child, "SIGTERM", {
+      platform: "win32",
+      runTaskkill,
+    });
+    expect(runTaskkill).toHaveBeenNthCalledWith(1, "taskkill", ["/PID", "12345", "/T"], {
+      stdio: "ignore",
+    });
+
+    runtimeSmoke.signalChildProcessTree(child, "SIGKILL", {
+      platform: "win32",
+      runTaskkill,
+    });
+    expect(runTaskkill).toHaveBeenNthCalledWith(2, "taskkill", ["/PID", "12345", "/T", "/F"], {
+      stdio: "ignore",
+    });
+    expect(child.kill).not.toHaveBeenCalled();
+  });
+
   it.runIf(process.platform !== "win32")("stops runtime gateway process groups", async () => {
     const runtimeSmoke = await importRuntimeSmokeWithEnv({
       OPENCLAW_BUNDLED_PLUGIN_RUNTIME_TEARDOWN_GRACE_MS: "50",