The study purpose was to investigate predictive associations between adolescent girls’ motivational predispositions to Physical Education (PE) and habitual physical activity. Two hundred girls (age 13.1 ± 0.6 years) completed the Physical Education Predisposition Scale and, the Physical Activity Questionnaire for Older Children. ANCOVAs revealed that girls with the highest Perceived PE Worth and Perceived PE Ability scores were the most habitually active groups (p < .0001). Significant predictors of physical activity identified by hierarchical regression were Perceived PE Ability and body mass index, which accounted for 17% and 3% of variance, respectively. As Perceived PE Ability was strongly associated with physical activity, the correlates of this construct should be further established to inform future school and PE-based interventions.