Sixty-four undergraduate males participated in an experiment designed to examine the effects of level of prior anger arousal, exposure to an aggressive model, and ambient temperature on physical aggression. On the basis of Bandura's social learning theory of aggression, it was predicted that uncomfortably hot environmental conditions would be most effective in facilitating later aggression when subjects had both witnessed the actions of the model and been exposed to strong provocation from the victim, but least effective in this regard when they had neither witnessed the actions of the model nor been exposed to prior instigation. In contrast to these predictions, results indicated that high ambient temperatures facilitated aggression by nonangered subjects but actually inhibited such behavior by those who had previously been provoked.