The present study investigated the development of global and domain-specific self-representations in the transition from late childhood to early adolescence and tested whether gender, puberty, and school transition help explain individual differences in change. The study was based on three measurement occasions over 2 years and included 248 adolescents (average age at T1 = 10.6 years). Findings indicated both stability and change over time. Individual differences in change were partially explained by gender and school transition. It revealed that girls experienced steeper decreasing trajectories and were more negatively affected by school transition in comparison with boys. Time-varying associations between puberty and self-representations were evident in terms of perceived pubertal timing. Findings suggest that both biological (pubertal timing) and contextual factors (school transition) play a role in explaining individual differences of self-representation level as well as their development in girls’ and boys’ transition to early adolescence.