Maintaining learning engagement throughout adolescence is critical for long-term academic success. This research sought to understand the role of metacognition and motivation in predicting adolescents' engagement in math learning over time. In two longitudinal studies with 2,325 and 207 adolescents (ages 11-15), metacognitive skills, interest, and self-control each uniquely predicted math engagement. Additionally, metacognitive skills worked with interest and self-control interactively to shape engagement. In Study 1, metacognitive skills and interest were found to compensate for one another. This compensatory pattern further interacted with time in Study 2, indicating that the decline in engagement was forestalled among adolescents who had either high metacognitive skills or high interest. Both studies also uncovered an interaction between metacognitive skills and self-control, though with slightly different interaction patterns.