diff --git a/packages/core/src/input/focusLock.ts b/packages/core/src/input/focusLock.ts
new file mode 100644
index 000000000..b9ed3255f
--- /dev/null
+++ b/packages/core/src/input/focusLock.ts
@@ -0,0 +1,61 @@
+// ─────────────────────────────────────────────────────
+// @termuijs/core — Scoped Keyboard Focus Lock & Modal Manager
+// ─────────────────────────────────────────────────────
+
+import type { FocusManager, Focusable } from '../events/FocusManager.js';
+
+export interface TrapOptions {
+  containerId: string;
+}
+
+export class FocusLockManager {
+  private _focusManager: FocusManager;
+  private _trapStack: string[] = [];
+
+  constructor(focusManager: FocusManager) {
+    this._focusManager = focusManager;
+  }
+
+  get isLocked(): boolean {
+    return this._trapStack.length > 0;
+  }
+
+  get activeTrapContainerId(): string | null {
+    if (this._trapStack.length === 0) return null;
+    return this._trapStack[this._trapStack.length - 1];
+  }
+
+  pushTrap(options: TrapOptions, focusables: Focusable[] = []): void {
+    this._trapStack.push(options.containerId);
+    this._focusManager.trap(options.containerId, focusables);
+  }
+
+  popTrap(): string | null {
+    if (this._trapStack.length === 0) return null;
+
+    const popped = this._trapStack.pop()!;
+    this._focusManager.release();
+
+    return popped;
+  }
+
+  handleKeyDown(keyName: string, isShift: boolean = false): boolean {
+    if (!this.isLocked) return false;
+
+    if (keyName === 'escape') {
+      this.popTrap();
+      return true;
+    }
+
+    if (keyName === 'tab') {
+      if (isShift) {
+        this._focusManager.focusPrev();
+      } else {
+        this._focusManager.focusNext();
+      }
+      return true;
+    }
+
+    return false;
+  }
+}
diff --git a/packages/core/test/focusLock.test.ts b/packages/core/test/focusLock.test.ts
new file mode 100644
index 000000000..8b5aed6d8
--- /dev/null
+++ b/packages/core/test/focusLock.test.ts
@@ -0,0 +1,53 @@
+import { describe, expect, test, beforeEach } from 'bun:test';
+import { FocusManager } from '../src/events/FocusManager.js';
+import { FocusLockManager } from '../src/input/focusLock.js';
+
+describe('FocusLockManager', () => {
+  let focusManager: FocusManager;
+  let focusLock: FocusLockManager;
+
+  beforeEach(() => {
+    focusManager = new FocusManager();
+    focusLock = new FocusLockManager(focusManager);
+
+    focusManager.register({ id: 'bg-btn', tabIndex: 1, focusable: true });
+    focusManager.register({ id: 'modal-btn1', tabIndex: 2, focusable: true });
+    focusManager.register({ id: 'modal-btn2', tabIndex: 3, focusable: true });
+    focusManager.start();
+  });
+
+  test('pushes trap and locks focus within container', () => {
+    expect(focusLock.isLocked).toBe(false);
+
+    focusLock.pushTrap(
+      { containerId: 'modal-1' },
+      [
+        { id: 'modal-btn1', tabIndex: 1, focusable: true },
+        { id: 'modal-btn2', tabIndex: 2, focusable: true },
+      ]
+    );
+
+    expect(focusLock.isLocked).toBe(true);
+    expect(focusLock.activeTrapContainerId).toBe('modal-1');
+  });
+
+  test('handles tab navigation cycling inside trap', () => {
+    focusLock.pushTrap({ containerId: 'modal-1' }, [
+      { id: 'modal-btn1', tabIndex: 1, focusable: true },
+      { id: 'modal-btn2', tabIndex: 2, focusable: true },
+    ]);
+
+    const handled = focusLock.handleKeyDown('tab');
+    expect(handled).toBe(true);
+  });
+
+  test('pops trap on escape key', () => {
+    focusLock.pushTrap({ containerId: 'modal-1' }, [
+      { id: 'modal-btn1', tabIndex: 1, focusable: true },
+    ]);
+
+    const handled = focusLock.handleKeyDown('escape');
+    expect(handled).toBe(true);
+    expect(focusLock.isLocked).toBe(false);
+  });
+});