ObjectiveWhether sleep is related to fundamental movement skills (FMS) in the pediatric population is largely unknown. The objective of this study was to examine the association between sleep characteristics (duration, efficiency, regularity) and FMS proficiency levels in school‐aged children.MethodsThis cross‐sectional study included 996 children (mean age: 8.3 ± 1.2 years) from 25 of the 32 primary schools in Matosinhos, northern Portugal. Data collection occurred between January and June 2022. Sleep was assessed using an ActiGraph wGT3X‐BT accelerometer worn on the wrist for 7 consecutive days. FMS proficiency levels were assessed in the schools with a new digital platform (Meu Educativo®) that evaluated five object control skills (dribble, kick, catch, throw, and underhand roll), with a total score ranging between 5 and 15. Multilevel ordinal logistic regression was used to test the associations between sleep characteristics and FMS proficiency levels. Covariates included age, sex, body mass index z‐score, socioeconomic status, and moderate‐to‐vigorous physical activity.ResultsThe results showed that sleep characteristics (duration, efficiency, and regularity) were not related to FMS proficiency. Being a boy, older age, and higher moderate‐to‐vigorous physical activity levels were all significantly associated with better FMS proficiency levels. There were no significant sex‐by‐age interactions.ConclusionSleep was not found to be related to FMS performance in children. This finding suggests that sleep is not a good correlate of FMS proficiency levels in school‐aged children, and attention should be dedicated to other more important factors such as skill‐learning‐specific physical activity.