We hypothesized and tested that cultural tightness -- the strength of social norms in a culture -- would influence people's sense of humor, particularly humor production. We found that participants from a tight culture (China) scored lower on humor production compared to participants from a loose culture (U.S.). The results are generalized to a broader sample involving four tight and three loose countries, including a tight (but individualist) culture and a loose (but collectivist) culture. A mini meta-analysis showed that humor production is negatively related to cultural tightness but unrelated to collectivism. Furthermore, we observed in experiments that cultural tightness hinders humor production. Drawing on cross-cultural evidence, the research unpacks culture and presents the first causal evidence of how cultural tightness influences humor. The findings have important implications for education, business, and innovation.