Very young infants are sensitive to and follow other people's gaze. By 18 months children, like chimpanzees, apparently represent the spatial relationship between viewer and object viewed: they can follow eye-direction alone, and react appropriately if the other's gaze is blocked by occluding barriers. This paper assesses when children represent this relationship as psychological in nature. Studies examining sensitivity to gaze, gaze following, and explicit judgement of gaze direction are reviewed. The evidence suggests that neither infants nor chimpanzees represent gaze as psychological. It is concluded that mentalistic gaze understanding develops from the age of 3 years.