This article presents findings from research investigating the effectiveness of humor appeals (humor relatedness and humor mechanisms) to Indonesian millennials for predicting their attitudes toward printed ads and their purchase intentions. In total, 543 Indonesian millennials participated in three experimental studies to test the relationship between humor appeals and the need for cognition to predict their attitudes and intentions. It was found that humor appeals were effective in predicting millennials’ attitudes toward printed ads and their purchase intentions. However, the need for cognition did not significantly influence the relationship. Indonesian millennials were more likely to not engage in thinking processes when evaluating humorous ads, which may be influenced by their characteristics and cultural backgrounds. © The Author(s) 2021.