This study sought to understand the extent to which elementary or middle school mobility was associated with adverse middle school academic achievement and mental health and whether youth or contextual characteristics moderated associations. I contrasted elementary and middle school mobility to consider whether a recent school move or elementary school move mattered for current adjustment and achievement. Using a diverse sample of youth from a mid-sized urban school district (N = 1,651), results from propensity score weighted regression models indicated that middle school but not elementary school mobility was associated with deficits in achievement and mental health. Results differed notably for girls and boys. Girls who changed schools demonstrated more depressive symptoms and had lower achievement than similar girls who did not. Moderated effects were also evident by receipt of free or reduced price lunch. Results are discussed in terms of future research and school policies to support mobile youth.