Risk behavior contributes to substantial morbidity and mortality during adolescence. This study examined neurocognitive predictors of proposed subtypes of adolescent risk behavior: planned (premeditated) versus unplanned (spontaneous). Adolescents (N = 69, 49% male, M = 15.1 [1.0] years) completed neurocognitive tasks (Iowa Gambling Task [IGT], and Game of Dice Task [GDT]) and a self-report measure indicating whether past-year risk behaviors were planned or unplanned. As hypothesized, identifying more beneficial choices on the neurocognitive tasks and perceiving benefits of risk behavior to outweigh costs predicted engagement in planned versus unplanned risk behavior. This study is the first to use neurocognitive assessments to differentiate planned and unplanned subtypes of risk behavior. Understanding mechanisms underlying these subtypes may inform prevention programs targeting specific contributors to adolescent risk behavior. (Contains 3 tables and 2 figures.)