Multisensory integration helps the brain build reliable models of the world and resolve ambiguities. Visual interactions with sound and touch are well established but vestibular influences on vision are less well studied. Here, we test the vestibular influence on vision using horizontally opposed motions presented one to each eye so that visual perception is unstable and alternates irregularly. Passive, whole-body rotations in the yaw plane stabilized visual alternations, with perceived direction oscillating congruently with rotation (leftward motion during leftward rotation, and vice versa). This demonstrates a purely vestibular signal can resolve ambiguous visual motion and determine visual perception. Active self-rotation following the same sinusoidal profile also entrained vision to the rotation cycle - more strongly and with a lesser time lag, likely because of efference copy and predictive internal models. Both experiments show that visual ambiguity provides an effective paradigm to reveal how vestibular and motor inputs can shape visual perception.