This disclosure describes techniques for device authentication and/or pairing. A display system can comprise a head mountable display, computer memory, and processor(s). In response to receiving a request to authenticate a connection between the display system and a companion device (e.g., controller or other computer device), first data may be determined, the first data based at least partly on audio data spoken by a user. The first data may be sent to an authentication device configured to compare the first data to second data received from the companion device, the second data based at least partly on the audio data. Based at least partly on a correspondence between the first and second data, the authentication device can send a confirmation to the display system to permit communication between the display system and companion device.