To evaluate the relationship between biologico-demographical, sociocultural, and environmental factors and the performance of physical activity in early childhood.A systematic search was carried out of the databases MEDLINE, EMBASE, CENTRAL, and LILACS, as well as Google Scholar, Open Grey, ClinicalTrials.gov, DARE, PROSPERO, Health Technology Assessment, and the World Health Organization International Clinical Trials Registry Platform, from their first records to June 2018. The selection criteria were previously defined with respect to population age and article theme. No meta-analyses were carried out due to the heterogeneity of the studies.The percentage of moderate to vigorous physical activity runs between 3% and 47%. Environmental and sociocultural factors were identified as exerting a greater influence on children's physical activity in early childhood, with the environmental factors being, according to almost all the study authors, the greater of the two.According to the studies included in this research project, the factors identified as associated with moderate to vigorous physical activity are environmental (play in open spaces) and sociocultural (the role of the family and the physical activity of the mother). The evidence is not strong enough to conclude that biologico-demographic factors are significantly influential in the physical activity at this age.