This study aimed to examine the contribution of objective measures of physical fitness (musculoskeletal and cardiorespiratory), physical activity and motor skill to motor perception. A total of 122 children (63 boys) aged 9-11 years were assessed. Independent t-tests assessed sex differences in all variables. Two linear mixed models adjusted for sex and age were performed with perceived object control and locomotor skills (pictorial scale of Perceived Movement Skill Competence for young children) as outcomes. Aerobic (multi-stage fitness test) and muscular fitness (long jump, grip strength), moderate-to-vigorous physical activity (ActiGraph accelerometry), movement skill (Test of Gross Motor Development-2), age and sex were predictors. Boys had higher object control skills (actual and perceived) and fitness. Age (decreasing) and long jump distance (positive) explained 16% of locomotor skill perception variance. Sex (boys) explained 13% of object control skill perception variance. Children’s skill self-perception may be influenced by fitness attributes as these are more evident to them. The fact that girls have lower actual object control competence and fitness than boys suggest girls may be an intervention target.