Adolescents take more risks with peers than when alone. It is not clear how peer presence affects adolescents' risky decision making, however. We used the Iowa Gambling Task (IGT)—a game used to assess decision making involving risk and reward—to examine how peers affect late adolescents' exploration of relevant environmental cues, ability to learn from the outcomes (positive and negative) of that exploration, and ability to integrate feedback to adjust behavior toward optimal long‐term outcomes. One hundred and one 18‐ to 22‐year old males (M = 19.8 years) were randomly assigned to play the IGT either alone or observed by peers. Late adolescents tested with observers engaged in more exploratory behavior, learned faster from both positive and negative outcomes, and evinced better task performance than those tested alone.