Locking the iPhone turns off normal access to the current screen and requires authentication according to your security settings before someone can use the device again.
Lock the iPhone Immediately
- Press the Side button once.
- Confirm that the display turns off or returns to the Lock Screen behavior for your model.
Set the iPhone to Lock Automatically
- Open Settings.
- Tap Display & Brightness.
- Tap Auto-Lock.
- Choose how long the iPhone should wait before locking.
Use a Secure Passcode
Screen locking is most useful when the iPhone has a strong passcode. Face ID or Touch ID makes routine unlocking convenient, but the passcode remains an important fallback security credential.
Always-On Display
On supported models, the Lock Screen can remain dimly visible even though the iPhone is locked. A visible clock or wallpaper therefore does not necessarily mean the device is unlocked.
If Auto-Lock Is Unavailable
Some settings, device-management policies, or power-related configurations can affect available Auto-Lock choices. Review those conditions before assuming the display setting is malfunctioning.
Review What Is Visible While Locked
A locked iPhone can still show selected notification previews, widgets, Control Center access, and other Lock Screen features depending on your settings. If privacy is the goal, review the options under Face ID & Passcode or Touch ID & Passcode so sensitive information is not exposed even though the phone itself is locked.
Locking Does Not Close Apps
Pressing the Side button locks the device but does not quit the apps you were using. When you unlock the iPhone, you can usually return to the same app and screen.