The relations between temperament, communicative competence, and humor expression were examined in a sample of 4and 5-year-old nursery-school chil dren (N = 158). Ratings of communicative competence and various dimensions of temperament accounted for a significant proportion of the variance in the re ported frequency of children's laughter and verbal and behavioral attempts at in itiating humor. Children who were normal-to-advanced in their level of commu nicative competence were rated as significantly more humorous than those assessed as delayed. Although the temperament characteristics of persistence/ attention span, distractibility, mood, and response threshold were associated with humor, activity level and approach were especially noteworthy in predict ing the various expressions of humor. Humor development is discussed as a function of learned communicative abilities and temperamental predispositions which influence humor in both a direct and indirect manner.