We used the Oculus Rift head-mounted display (consumer release -CV1) to simulate forward self-motion in depth. Observers made continuous yaw head movements at approximately 0.5 Hz or 1.0 Hz while viewing these selfmotion simulations. We examined the perceptual effects of increasing the head-to-display lag, by adding lag to the baseline lag of the system (estimated to be approximately 5.3 ms). We found that increasing the head-to-display lag up to 212 ms reduced the presence and the strength of the illusory self-motion (vection). In addition, faster (1.0 Hz) head oscillations were found to generate weaker presence and vection than the slower (0.5 Hz) head oscillations. Both vection and presence in virtual environments can therefore be impaired by either increasing head-display lag or making more rapid angular head movements.