The role of peers in adolescents' sexual behaviors is not yet fully understood. We investigated the association between sexual communication with friends (at T1) and subsequent changes in adolescents' experience with sexual behaviors (between T1-T3), and examined whether this association was explained by adolescents' perceptions of three sexual peer norms (at T2): (1) peers' sexual behaviors (descriptive norms), (2) peers' approval of sexual behaviors (injunctive norms), and (3) peer pressure to have sex. The data source was Project STARS, a longitudinal study on adolescent sexual development in the Netherlands, collected via online self-report questionnaires from 1,116 adolescents (11.5-17.9 years). Adolescents who communicated more frequently with their friends about sexuality-related topics at T1 reported significantly larger increases in their experience with different sexual behaviors between T1-T3. More sexual communication with friends also predicted adolescents subsequently perceiving more 1) peer sexual behaviors, 2) peer approval of sex, and 3) peer pressure to have sex. These stronger perceptions, in turn, predicted larger increases in their sexual behaviors between T1-T3. After adjusting for the three norms simultaneously, the main association between sexual communication with friends and sexual behavior change weakened but remained significant. Inspection of specific indirect effects showed this link was explained by injunctive norms only. No gender differences were found.