While transitions to college can be stressful, links between distinct types of college transitions and changing student well-being remain unclear. For instance, peer ability often shifts from high school to college, though students differ markedly in how much peer ability change they experience. Here, we draw on national longitudinal data (National Longitudinal Study of Adolescent to Adult Health [Add Health]; Waves 1 and 3; N = 1,453) to demonstrate how peer ability transitions from high school to college relate to changes in depressive symptoms and self-esteem, net of student personal background and school-average levels of peer ability. We find that depressive symptoms increase by 27% for students experiencing lowered peer ability across their college transition, relative to no substantial change in peer ability. Meanwhile, heightened peer ability in college links to neither diminished nor enhanced student well-being across the transition. Overall, student well-being relates more closely to collegiate than high-school peer ability.