Physical Education, that is a subject where physical activity and sports dominate, has become to be considered as non-academic subject. It might easily be inferred from this that high academic grades can be achieved just by practicing sports while other factors, such as the student's interest and effort, would be irrelevant. Therefore, the present study examined the relationship between the academic achievement in physical education, persistence-effort, extracurricular sports and the academic and physical self-concept of students enrolled in the last courses of primary education. A sample of 224 students (aged 10-13; M = 10.98, SD = 0.71) participated in the study. Multiple regression analysis showed hat academic achievement in physical education was better explained by academic self-concept, followed by extracurricular sport and physical self-concept, F(3, 216) = 12.341, p <.000, R-2 =.15. Differences were found in these results according to gender, V =.064, F(4, 213) = 3.643, p =.007, eta(2)(p) =.064, and academic achievement, V =.093, F(4, 213) = 5.492, p <.001, eta(2)(p) =.093. Male students manifested higher levels of extracurricular sport and physical self-concept. On the other hand, students with high academic achievement showed higher levels in all variables except extracurricular sport. These findings suggest that, likewise happens in other subjects, the academic variables plays an important role in predicting academic achievement in physical education.