This experiment examines the notion that the sharing of humor enhances overt expressive responses (laughter and smiling) and humor ratings. Independent groups of seven- to eight-year-old children listened on headphones to amusing material. They were tested alone or in dyads or triads with confederates of the same sex. In triads, duration of laughter and smiling was inversely related to the amount that confederates looked at one another; this was the case whether confederates were thought to be listening to the same or different recordings. Laughter and smiling scores support the notion that sharing the social situation is crucial in the facilitation of "humorous laughter." A theory of socially facilitated laughter is proposed which draws upon social-facilitation drive theory and the tension-reduction aspects of humor theory.