It is well known that self-efficacy positively affects students' learning behavior. However, less is known about this association in self-directed learning, which additionally promotes student's control strategies. To close this gap, this study tested whether control strategies mediate the association between self-efficacy and effort investment, absorption, and elaboration, considering potential age-specific differences in a sample of 754 secondary school students in self-directed learning classes (M[subscript age] = 13.56; SD = 1.2). Multigroup structural equation modeling and latent mean comparison was used to assess potential age-related differences (6th-7th grades and 8th-9th grades) in the proposed model. Results have shown that control strategies mediate all existing relationships, although these associations are stronger in the group of older adolescents. Interestingly, adolescents of both age groups do not differ in the magnitudes of self-efficacy and elaboration. However, older students report lower values in control strategies, effort investment, and absorption.