Adolescents who experience changes in parents’ union status are more likely than adolescents in stable family structures to engage in problem behavior. We ask whether the link between family structure transitions and problem behavior in adolescence may be explained in part by the residential and school mobility that co-occur with family structure change. Our analysis uses nationally-representative data from a two-generation study to assess the relative effects of family instability and mobility on the self-reported problem behavior of adolescents who were 12–17 years old in 2006. Residential and school mobility only minimally attenuate the association of family structure changes with behavior problems for younger girls and older adolescents. Exposure to peer pressure has a larger attenuating effect. We conclude that although mobility often co-occurs with family structure change, it has independent effects on problem behavior.