Children's positive perceived motor competence (PMC) provides motivation for physical activity. Theoretically young children (<8 years) have inflated PMC but as children cognitively develop, perceptions are hypothesized to decrease. This study investigated strength of PMC association over time, whether any change was negative (i.e. PMC decreased) and sex differences. A total of 198 children participated, 88 (44.4%) girls and 110 (55.6%) boys, aged 8.37-11.3 years at time point one (T1). Test--retest reliability using intraclass correlation was moderate for locomotor and moderate-to-good for object control perception. Hierarchical regression analysis showed PMC at T1 positively predicted significant variance one year later (T2) for locomotor (23.1%) and object control skill (5 items: 37.7%; 7 items: 39.9%). Whilst boys and girls differed on perception level there was no interaction between PMC and sex. Incongruent with previous theoretical perspectives this study identified stability in children's PMC across an important developmental period.