We conducted an experiment in a high-immersive virtual reality environment to study the effect of the presence of a virtual observer on cheating behavior. Par- ticipants were placed in a virtual room and played 30 rounds of a cheating game without a chance of their cheating being detected. We varied whether or not a vir- tual observer (an avatar) was present in the room, and, if so, whether the avatar was actively staring at the decision maker or passively seated in a corner watching his smartphone. Results display significantly less cheating with an active than with a passive avatar, but not less cheating than in a control condition without an avatar. This suggests that an active (virtual) observer can intensify reputational concerns, but that the presence of someone passive and uninterested may actually alleviate such concerns.