We examined the association between intellectual humility (IH)-a willingness to consider credible new information and alternative views and revise one's own views if warranted-and adherence to experts' health behavior recommendations in the U.S. during the COVID-19 pandemic. Study 1 ( N = 541) results showed that people higher in IH are more likely to engage in recommended health behaviors (e.g., mask-wearing, social distancing)-even when controlling for political affiliation. Additional analyses focused specifically on mask-wearing produced initial evidence consistent with mediation of the IH-mask-wearing relationship by the beliefs that mask-wearing 1) is an effective way to slow the spread of COVID-19 and 2) protects others. Based on the pathway from IH to mask-wearing through a concern for others found in Study 1, Study 2 further examined the relationship between IH and prosocial tendencies. The results from Study 2 ( N s for correlation coefficients ranged from 265 to 702) showed an association between IH and several values and traits that reflect a concern for others (e.g., agreeableness, benevolence). These findings suggest that IH may influence behavior through both intra- and interpersonal mechanisms. Implications of these findings for the health-behavior domain are discussed.