We investigated children's understanding of irony and sensitivity to irony's meanness and humor. In Study 1, 89 participants (5-6-year-olds, 8-9-year-olds, adults) heard ironic and literal criticisms, and literal compliments. Comprehension of irony emerged between 5 and 6 years of age. Ratings of humor increased with age; ratings of meanness did not (showing that all ages perceived irony as more muted than literal criticism). In Study 2, results from 135 participants (6-7-year-olds, 8-9-year-olds, and adults) replicated these findings and revealed the role of form and intonation. Thus, comprehension of irony emerges between 5 and 6 years of age, and sensitivity to the muting function develops prior to sensitivity to the humor function.