A system and/or method is provided to implement authentication via Bluetooth devices. In particular, a user's Bluetooth device, such as a smart phone, may be registered to be used for automatic authentication for an online user account. When the user is attempting to log onto the online user account at a user device, such as a laptop, the user device may detect that the user's Bluetooth device is in proximity to the user device and the user may be logged into the online user account at the user device automatically. Thus, the user may be logged into the online user account seamlessly without requiring the user to input credentials, such as user name and/or password.