In aspects of fingerprint authentication based on fingerprint imager orientation, a mobile device has a first housing moveably connected to a second housing in a device configuration that is one of a closed configuration in which the first housing and the second housing are rotated and folded together, or an open configuration in which the first housing and the second housing are rotated apart. The mobile device includes a fingerprint imager to capture a fingerprint image in either device configuration of the mobile device. The mobile device also includes an authentication module to determine an orientation of the fingerprint imager based on the device configuration, manipulate the captured fingerprint image to align with a reference fingerprint image, and authenticate the captured fingerprint image as manipulated to align with the reference fingerprint image for access to the mobile device.