Citizens’ willingness to participate in political and civic life is crucial for democracies. The Civic Voluntarism Model has frequently been used to explain political participation by emphasizing citizens’ resources, psychological engagement, and recruiting as important antecedents. While the model has received extensive support from cross-sectional studies among adults, we know little about its explanatory power for the development of adolescents’ willingness to participate. Thus, this study aims to determine whether and how adolescents’ resources (i.e., political knowledge, socioeconomic background, cultural capital), psychological engagement (political interest and efficacy), and recruitment (peers’ participatory attitudes, discussions, and school track) are related to the development of three types of willingness to participate (civic engagement, activism, voting) among high school students from Grade 7 to 8. For this purpose, we performed cross-sectional and longitudinal analyses with data from N = 444 students. Overall, our structural equation models indicated positive associations between the Civic Voluntarism Model components and willingness to participate, with considerable variation between the cross-sectional and longitudinal analyses. For the cross-sectional analyses, we found positive associations between political interest and all examined forms of willingness to participate. In the longitudinal analyses, we found that socioeconomic background was related to all forms of willingness to participate. The results for other factors varied depending on the type of political participation. Future studies should strive to systematically investigate these differences and inspect the specific interplay between factors. The consistent longitudinal findings on socioeconomic statues point to the need to counteract political inequality through measures such as civic education.