Information and communication technology (ICT) literacy encompasses a range of cognitive abilities that facilitate the effective use of digital technologies. Two studies on German students investigated the role of reading comprehension and mathematical competence in the development of ICT literacy in adolescence. A variance decomposition analysis (N = 13,335) revealed that both competence domains together accounted for nearly half of the explained item variances in two ICT literacy assessments. Additionally, a cross-lagged panel analysis (N = 4,872) demonstrated that reading and mathematical competencies predicted ICT literacy growth over three years, while ICT literacy also had reciprocal effects on domain-specific competencies. These findings emphasize that ICT literacy is not merely a technical skill set but is also closely related to other cognitive abilities.