diff --git a/src/main/commandRunner.ts b/src/main/commandRunner.ts
index 9bbe9e6..218fb0c 100644
--- a/src/main/commandRunner.ts
+++ b/src/main/commandRunner.ts
@@ -155,3 +155,23 @@ export function killAllRunningCommands(): void {
   }
   running.clear()
 }
+
+// Stops every running project's containers in one shot (equivalent to
+// `ddev stop` on each of them, but faster) so nothing is left running in the
+// background after the app quits. Resolves rather than rejects on any
+// failure — a missing/unresponsive ddev or docker shouldn't block quitting —
+// and the timeout guards against poweroff hanging if the docker daemon is
+// stuck, which would otherwise stall app exit indefinitely.
+export function powerOffAllProjects(): Promise<void> {
+  return new Promise((resolve) => {
+    const child = spawn('ddev', ['poweroff'], { env: ENV_WITH_DDEV_PATH, stdio: 'ignore' })
+    const timeout = setTimeout(() => child.kill(), 10_000)
+
+    const finish = (): void => {
+      clearTimeout(timeout)
+      resolve()
+    }
+    child.on('error', finish)
+    child.on('close', finish)
+  })
+}
diff --git a/src/main/index.ts b/src/main/index.ts
index e184929..e06bb0b 100644
--- a/src/main/index.ts
+++ b/src/main/index.ts
@@ -9,7 +9,7 @@ import { registerAddonsIpc } from './ipc/addons'
 import { registerLogsIpc } from './ipc/logs'
 import { registerCreateIpc } from './ipc/create'
 import { registerWindowIpc } from './ipc/window'
-import { killAllRunningCommands } from './commandRunner'
+import { killAllRunningCommands, powerOffAllProjects } from './commandRunner'
 import { warmupDdevImagesIfNeeded } from './imageWarmup'
 
 function createWindow(): void {
@@ -89,10 +89,19 @@ app.on('window-all-closed', () => {
   }
 })
 
-// Kill any still-running ddev processes (e.g. an open `ddev logs -f` stream)
-// so they don't linger as orphans after the app exits.
-app.on('before-quit', () => {
+// Kill any still-running ddev processes (e.g. an open `ddev logs -f` stream),
+// then power off every running project so sites don't keep running in the
+// background after the app exits. Quit is deferred until poweroff finishes
+// (or times out), so this intercepts the first before-quit and re-fires
+// app.quit() itself once cleanup is done — the isQuitting guard stops that
+// from looping back into this handler.
+let isQuitting = false
+app.on('before-quit', (event) => {
+  if (isQuitting) return
+  event.preventDefault()
+  isQuitting = true
   killAllRunningCommands()
+  void powerOffAllProjects().finally(() => app.quit())
 })
 
 // In this file you can include the rest of your app's specific main process