In adolescence, externalized problems such as risk taking and antisocial behavior are more frequent in boys. This suggests that there are differences in the way boys and girls evaluate risk and make decisions during this period. To explore decision making and highlight possible gender differences, 124 adolescents at a junior secondary school completed two decision-making tasks: The Iowa Gambling Task (Bechara, Damasio, Damasio, & Anderson, 1994) and the Rogers Betting Task (Rogers et al., 1999). The results indicate that girls make more advantageous decisions on the Gambling Task and boys take more risks during the Betting Task. These results are discussed in light of the differing development of emotion, cognition, and brain structures in boys and girls. (Contains 5 tables and 2 figures.)