The purpose of this systematic review was to examine the influence of relative age effect (RAE) on motor competences (MC) and physical fitness (PF) of preschool children. The search was conducted through three different databases: Web of Science, Scopus and EBSCO up to 11 August 2023. This study was conducted and reported according to the PRISMA statement. Out of 2494 studies, 10 studies fulfilled the inclusion criteria. Five studies investigated the influence of RAE on MC, while five examined its influence on PF in children aged 3-6 years. According to the main results of these studies, children born in the first quarter had significantly higher scores in MC and PF. However, there is a tendency for RAE decreases as age increases. Due to method and sample differences of the studies, further research are required to understand better the existence of RAE on motor performance skills in preschoolers.