Sleep problems have become a public health epidemic with recent data suggesting that more than 69% of U.S. adults get less sleep than they need. Despite the important role that sleep plays in our lives, sleep as a variable of interest in interpersonal processes has been historically absent from the psychological literature. Recently, however, researchers have shed some light on the link between sleep and a wide array of social processes. This work illuminates the important role that sleep plays in our social experiences, from basic social perception to complex social interactions. We outline a working model for the bidirectional link between sleep and social processes, including underlying mechanisms; review the recent research that informs this model; and use it to elucidate important next steps to bring together sleep and social psychological research. We also address the pragmatics of measuring sleep for non–sleep researchers.