The present study focuses on political efficacy in terms of students' competence self-perceptions related to the domain of politics. The investigation addresses the mean level development and longitudinal relations to outcome variables including gender differences. Drawing on a sample of N = 2,504 German students, political efficacy, along with meaningful outcome variables (i.e., political information behavior, political knowledge, and interest in politics), was measured at 2 measurement points, once in Grade 7 and once in Grade 10. Students' mean levels of political efficacy increased from the first to the second measurement point, and boys consistently displayed higher levels. Political efficacy demonstrated reciprocal relations to political information behavior and political knowledge, and showed a unidirectional relation to interest in politics across time. The pattern of outcome relations was invariant across gender. This study contributes to research and theory on political socialization in adolescence as it outlines temporal relations among, and gender differences in, facets of political socialization. Therefore, this study also offers new practical insights into effectively facilitating political education in adolescent students.