OBJECTIVE: The aim was to study effects on motor skills and self-esteem of an extension of the Swedish school subject Physical Education and Health (PEH) and motor training during nine school years. DESIGN AND METHOD: An intervention group (n=161) had PEH and motor training five lessons (225 min) and a matched control group (n=102) had regular PEH two lessons (90 min) per week. The method was hypothetico-deductive. RESULTS AND CONCLUSIONS: The hypothesis that students’ motor skills improve with extended physical activity and motor training was confirmed. The school has good potential in stimulating all students’ development of motor skills, but two lessons of PEH per week are not enough. Significant correlations were found between motor skills and self-esteem overall and the components friendship/ sports efficacy and attention/learning efficacy. Differences in self-esteem between students with good motor skills and students with deficits may decrease with extended physical activity and motor training in school.