Abstract: In order to better understand how scene motion is perceived in immersive virtual environments, we measured scene-motion thresholds under different conditions across three experiments. Thresholds were measured during quasi-sinusoidal head yaw, single left-to-right or right-to-left head yaw, different phases of head yaw, slow to fast head yaw, scene motion relative to head yaw, and two scene-illumination levels. We found that across various conditions (1) thresholds are greater when the scene moves with head yaw (corresponding to gain $<$1.0) than when the scene moves against head yaw (corresponding to gain $>$1.0), and (2) thresholds increase as head motion increases.