Adolescence is a time of psychological transition and vulnerability. Youth who have been exposed to adverse family environments, particularly those having experienced maltreatment, are especially at risk for emotional and behavior problems. One important factor that may predict adolescents’ emotional well-being and behavior is their implicit beliefs about whether or not emotion can be controlled. The current study examines the links between implicit theories of emotion and internalizing symptoms and aggression in a sample of high-risk youth ages 10 to 17. 112 of the participants were maltreated and the remaining 69 formed a control group. Adolescents who expressed greater perceived control over their emotion reported lower levels of internalizing and aggressive behaviors. Although mean levels of implicit theories did not differ between maltreated and control groups, there was a trend towards maltreated youth being less likely to view their emotions as controllable compared to non-maltreated youth. These findings indicate that adolescents’ mindsets regarding the controllability of their emotions may have important implications for their mental health.