News media play a key role in informing young citizens about politics and cultivating a sense of political efficacy. Online news media, in particular, are expected to have a positive impact due to their interactivity and new opportunities to share and discuss information. This study analyzes the impact of online and offline news media use on the growth in internal efficacy among adolescents, based on data we collected in a three-wave panel survey in the Netherlands (N = 729). Additionally, we test the impact of internal efficacy on turnout using a fourth wave of the same sample (N = 612). The results show that while newspaper reading has the strongest effects among traditional news sources, actively participating in the communication process of political information online has the strongest impact on internal efficacy. Internal efficacy in turn is found to be a significant predictor of first-time voters. The article concludes with a discussion of media use as a pathway to political participation through internal political efficacy.