Despite a growing consensus that civic education is an important aspect of political socialization, little research has prospectively examined how gains made during civics courses are maintained after high school. This study used a quasi-experimental design to examine longer-term effects of the Student Voices program, which was originally evaluated in Philadelphia public high schools during the 2002-2003 school year. Following the 2004 presidential election, researchers recontacted students who had participated in the program for one or two semesters and students who had been in control civics classrooms. A structural equation model indicated that students who experienced two semesters of the program reported greater self-efficacy for political participation and that this effect carried over to increased political attentiveness as well as to knowledge of candidate positions. In addition, political attentiveness increased knowledge and voting in the election. However, neither knowledge nor efficacy had direct effects on voting once attentiveness was controlled. The results suggest that a supplementary civics education program such as Student Voices can increase subsequent participation in politics by building long-term gains in political self-efficacy and skills in using the news media to follow government and political affairs.