Purpose: Guided by Stodden et al.'s (2008) conceptual model, the purpose of this study was to examine the associations among perceived competence, actual motor competence (MC), physical activity (PA), and cardiorespiratory fitness in elementary children. The group differences were also investigated as a function of MC levels. Methods: A correlational research design was used in this study. There were 262 children (M[subscript age] = 10.87, SD = 0.77) recruited from three schools in the southern U.S. Students' MC was objectively measured based on a process-oriented assessment (PE Metrics, NASPE, 2010). Students self-reported perceived competence and leisure-time PA. Then, the Progressive Aerobic Cardiovascular Endurance Run (PACER) and pedometers were used to measure students' cardiorespiratory fitness and in-class PA, respectively. Results: The structural equation modeling analysis supported the significant indirect effect of the MC on cardiorespiratory fitness and PA through perceived competence. The MANCOVA yielded a significant main effect for MC groups after controlling for sex [Wilks's Lambda = 0.838, F = 12.15 (4, 251), p < 0.001, ?[superscript 2] = 0.16]. Regardless of sex, children with low MC demonstrated lower perceived competence, PA, and cardiorespiratory fitness compared with children with higher MC (p < 0.001). Discussion: Development of students' competence beliefs in PE and certain movement patterns should be emphasized, especially during middle childhood. High quality PE programs must be aligned with national standards, with particular attention to enhancing skill acquisition (standard 1) and PE-motivation (i.e., perceived competence; standard 5).