diff --git a/packages/0/src/composables/index.ts b/packages/0/src/composables/index.ts
index 0f1363371..d0c0df430 100644
--- a/packages/0/src/composables/index.ts
+++ b/packages/0/src/composables/index.ts
@@ -41,6 +41,7 @@ export * from './useEventListener'
 export * from './useFeatures'
 export * from './useHotkey'
 export * from './useHydration'
+export * from './useIdle'
 export * from './useImage'
 export * from './useIntersectionObserver'
 export * from './useLazy'
diff --git a/packages/0/src/composables/useIdle/index.ts b/packages/0/src/composables/useIdle/index.ts
new file mode 100644
index 000000000..18d21369c
--- /dev/null
+++ b/packages/0/src/composables/useIdle/index.ts
@@ -0,0 +1,242 @@
+/**
+ * @module useIdle
+ *
+ * @see https://0.vuetifyjs.com/composables/system/use-idle
+ *
+ * @remarks
+ * Tracks user inactivity with optional warn stage and pause / resume control.
+ *
+ * Key features:
+ * - Reactive `stage`, `isIdle`, `isWarning`, `isPaused`, and `lastActivity`
+ * - Reactive `timeout`, `warnAt`, and `events` (re-register / re-schedule on change)
+ * - Optional warn stage before idle for "you'll be logged out in 30s" patterns
+ * - pause / resume (fresh re-schedule on resume — elapsed time is not preserved)
+ * - Reset on tab-visibility change (opt-out)
+ * - Automatic cleanup on scope disposal
+ * - SSR-safe
+ *
+ * @example
+ * ```ts
+ * import { useIdle } from '@vuetify/v0'
+ *
+ * const idle = useIdle(
+ *   stage => stage === 'idle' ? logout() : showWarning(),
+ *   { timeout: 10 * 60_000, warnAt: 9 * 60_000 },
+ * )
+ * ```
+ */
+
+// Composables
+import { useDocumentEventListener, useWindowEventListener } from '#v0/composables/useEventListener'
+
+// Globals
+import { IN_BROWSER } from '#v0/constants/globals'
+
+// Utilities
+import { isUndefined } from '#v0/utilities'
+import { onScopeDispose, shallowReadonly, shallowRef, toRef, toValue, watch } from 'vue'
+
+// Types
+import type { MaybeRefOrGetter, Ref } from 'vue'
+
+const DEFAULT_EVENTS: (keyof WindowEventMap)[] = [
+  'mousemove',
+  'mousedown',
+  'keydown',
+  'touchstart',
+  'scroll',
+  'wheel',
+]
+
+export type IdleStage = 'active' | 'warn' | 'idle'
+
+export interface UseIdleOptions {
+  /**
+   * Milliseconds of inactivity before transitioning to `'idle'`.
+   *
+   * @default 60000
+   *
+   * @example
+   * ```ts
+   * useIdle(handler, { timeout: 5 * 60_000 })
+   * useIdle(handler, { timeout: () => fast.value ? 1_000 : 60_000 })
+   * ```
+   */
+  timeout?: MaybeRefOrGetter<number>
+  /**
+   * Milliseconds of inactivity before transitioning to `'warn'`. Must be less
+   * than `timeout`. When undefined — or when `warnAt >= timeout` — the warn
+   * stage is silently skipped.
+   *
+   * @default undefined
+   *
+   * @example
+   * ```ts
+   * useIdle(handler, { timeout: 600_000, warnAt: 540_000 })
+   * ```
+   */
+  warnAt?: MaybeRefOrGetter<number | undefined>
+  /**
+   * Window events that count as user activity.
+   *
+   * @default ['mousemove', 'mousedown', 'keydown', 'touchstart', 'scroll', 'wheel']
+   *
+   * @example
+   * ```ts
+   * useIdle(handler, { events: ['keydown', 'pointerdown'] })
+   * ```
+   */
+  events?: MaybeRefOrGetter<(keyof WindowEventMap)[]>
+  /**
+   * Whether to start in the idle state.
+   *
+   * @default false
+   */
+  initialState?: boolean
+  /**
+   * Reset to active when the user switches back to this tab.
+   *
+   * @default true
+   */
+  resetOnTabSwitch?: boolean
+}
+
+export interface UseIdleContext {
+  /** Current stage. */
+  stage: Readonly<Ref<IdleStage>>
+  /** True when `stage === 'idle'`. */
+  isIdle: Readonly<Ref<boolean>>
+  /** True when `stage === 'warn'`. */
+  isWarning: Readonly<Ref<boolean>>
+  /** True when detection is paused. */
+  isPaused: Readonly<Ref<boolean>>
+  /** Epoch milliseconds of the most recent activity. */
+  lastActivity: Readonly<Ref<number>>
+  /** Mark the user as active and restart the countdown. No-op while paused. */
+  reset: () => void
+  /** Pause detection, clearing any pending warn / idle transition. */
+  pause: () => void
+  /** Resume detection. Re-schedules fresh from the current `timeout` / `warnAt`. */
+  resume: () => void
+}
+
+/**
+ * Tracks user inactivity with optional warn stage and pause control.
+ *
+ * @param callback Optional callback fired on each forward transition (`'warn'` or `'idle'`).
+ * @param options Idle detection options.
+ * @returns Reactive idle state and controls.
+ *
+ * @see https://0.vuetifyjs.com/composables/system/use-idle
+ *
+ * @example
+ * ```ts
+ * const { isIdle } = useIdle(undefined, { timeout: 5_000 })
+ *
+ * useIdle(
+ *   stage => stage === 'idle' ? logout() : showWarning(),
+ *   { timeout: 600_000, warnAt: 540_000 },
+ * )
+ * ```
+ */
+export function useIdle (
+  callback?: (stage: 'warn' | 'idle') => void,
+  options: UseIdleOptions = {},
+): UseIdleContext {
+  const {
+    timeout = 60_000,
+    warnAt,
+    events = DEFAULT_EVENTS,
+    initialState = false,
+    resetOnTabSwitch = true,
+  } = options
+
+  const stage = shallowRef<IdleStage>(initialState ? 'idle' : 'active')
+  const isIdle = toRef(() => stage.value === 'idle')
+  const isWarning = toRef(() => stage.value === 'warn')
+  const isPaused = shallowRef(false)
+  const lastActivity = shallowRef(Date.now())
+
+  let warnId: ReturnType<typeof setTimeout> | undefined
+  let idleId: ReturnType<typeof setTimeout> | undefined
+
+  function clear () {
+    if (!isUndefined(warnId)) {
+      globalThis.clearTimeout(warnId)
+      warnId = undefined
+    }
+    if (!isUndefined(idleId)) {
+      globalThis.clearTimeout(idleId)
+      idleId = undefined
+    }
+  }
+
+  function schedule () {
+    clear()
+    if (!IN_BROWSER || isPaused.value) return
+
+    const idleMs = toValue(timeout)
+    const warnMs = toValue(warnAt)
+
+    if (!isUndefined(warnMs) && warnMs > 0 && warnMs < idleMs) {
+      warnId = globalThis.setTimeout(() => {
+        stage.value = 'warn'
+        callback?.('warn')
+        idleId = globalThis.setTimeout(() => {
+          stage.value = 'idle'
+          callback?.('idle')
+        }, idleMs - warnMs)
+      }, warnMs)
+    } else {
+      idleId = globalThis.setTimeout(() => {
+        stage.value = 'idle'
+        callback?.('idle')
+      }, idleMs)
+    }
+  }
+
+  function reset () {
+    lastActivity.value = Date.now()
+    stage.value = 'active'
+    schedule()
+  }
+
+  function pause () {
+    if (isPaused.value) return
+    isPaused.value = true
+    clear()
+  }
+
+  function resume () {
+    if (!isPaused.value) return
+    isPaused.value = false
+    schedule()
+  }
+
+  useWindowEventListener(() => toValue(events), reset, { passive: true })
+
+  if (resetOnTabSwitch) {
+    useDocumentEventListener('visibilitychange', () => {
+      if (document.visibilityState === 'visible') reset()
+    })
+  }
+
+  watch([() => toValue(timeout), () => toValue(warnAt)], () => {
+    if (stage.value === 'active' && !isPaused.value) schedule()
+  })
+
+  if (!initialState) schedule()
+
+  onScopeDispose(clear, true)
+
+  return {
+    stage: shallowReadonly(stage),
+    isIdle,
+    isWarning,
+    isPaused: shallowReadonly(isPaused),
+    lastActivity: shallowReadonly(lastActivity),
+    reset,
+    pause,
+    resume,
+  }
+}