User Authentication Facilitated by an Additional Device

In aspects of user authentication facilitated by an additional device, a computing device can maintain authentication data usable to authenticate a user to use the computing device. The computing device implements an authentication control module that can determine an additional device is equipped to facilitate authentication of a user to the computing device. The authentication control module can then receive additional authentication data associated with the user from the additional device, and authenticate the user to use the computing device based in part on the additional authentication data received from the additional device.