PURPOSE: This study aimed to describe the changes in adolescents' perceptions of a sexual double standard (SDS) over time and to examine the developmental and social factors associated with these changing perceptions. METHODS: The sample includes 2,163 10- to 14-year-old adolescents from Kinshasa, interviewed at two time points (T0 and T1), 1 year apart. We examined associations between SDS and pubertal onset, family interactions, peer interactions, and media exposure. We conducted sex-stratified generalized estimation equation models to test associations between changes in SDS and sociodevelopmental factors at T0 as well as with changes in sociodevelopmental factors between T0 and T1. RESULTS: At T0, the SDS score was 4.15/5 among boys and 4.43/5 among girls, signaling highly gender unequal perceptions. SDS scores increased over time, shifting toward greater inequality. Adolescents who were prepubertal at T0 experienced greater increases in SDS scores than those who were pubertal at T0. The greatest increase in SDS scores was observed among girls who transitioned through puberty between T0 and T1. High parental monitoring of boys mitigated the increase in SDS as did boys' increased exposure to social media between T0 and T1. Girls who had mixed-sex friendships also experienced less change in SDS perceptions compared with those who socialized in same-sex groups. CONCLUSIONS: Puberty was associated with changes in SDS perceptions for all adolescents, whereas family interactions and media exposure affected changes in SDS perceptions for boys and peer interactions affected changes in SDS perceptions for girls.