Background—Previous studies have shown that choice and self-initiated behavior change are important for increasing intrinsic motivation and physical activity (PA), however, little of this research has focused on underserved adolescents. Purpose—This study examined the effects of a 4-week student-centered intervention on increasing PA in underserved adolescents. Methods—Twenty-eight students in the intervention school were matched (on race, percentage on free or reduced-price lunch program, gender, and age) with 20 students from another school who served as the comparison group (30 girls, 18 boys; ages 10–12 years; 83% African American; 83% on free or reduced-price lunch). The student-centered intervention was consistent with selfdetermination (motivation) theory and social cognitive theory in that it emphasized increasing intrinsic motivation and behavioral skills for PA. Intervention adolescents took ownership in selecting a variety of PA activities in which to participate, and they generated coping strategies for making effective PA behavior changes. Results—Intervention participants showed greater increases in accelerometer estimates of time spent in moderate PA, moderate-to-vigorous PA, and vigorous PA from baseline to Week 4 of the intervention than the comparison group. Intervention participants also showed greater increases in PA motivation and positive self-concept for PA than comparison adolescents. Conclusions—This study provides preliminary evidence that increasing adolescent involvement and choice of activities may be important in developing future PA interventions for underserved adolescents.