Objective: This study examined extracurricular and physical activity related to ADHD (diagnosis and symptoms) and cognitive disengagement syndrome (CDS) symptoms. Methods: Participants were 302 adolescents (ages 12-14) with and without ADHD and primary caregivers. ADHD diagnosis was determined with parent interview. Questionnaires provided information on parent-reported demographic characteristics, ADHD symptoms, and extracurricular activity involvement; and adolescent-reported ADHD and CDS symptoms and indices of physical activity. Results: Although ADHD diagnosis and symptom dimensions were correlated with less extracurricular and physical activity involvement, CDS symptoms were most often independently associated with these outcomes. Females and adolescents from lower income homes also often had less involvement in extracurricular and physical activity. Conclusions: Findings point to the need for more research in this area, careful assessment of risk factors (i.e., CDS symptoms, economic burden), and interventions that address inactivity in adolescents with ADHD, including those that address inequity related to income and sex.