BACKGROUNDSeveral studies have reported low adherence to World Health Organization sedentary behaviour guidelines in the early years. The purpose of this review is to test for associations between time spent in different types of sedentary behaviour (screen time, habitual sedentary behaviour) and motor competence (fundamental motor skills, fine and gross motor skills, locomotor skills, object control and balance) in 3–4-year-olds.METHODSFive databases were searched on the 27thof July 2021 with an updated search conducted on the 30thof September 2023: Web of Science (core collection), PUBMED Central, EMBASE (Ovid), SPORT Discus and ERIC. Studies were included in the review if they reported on an association between time spent in sedentary behaviour at ages 3-4 years and motor competence. The methodological quality for each of the included studies was assessed using Joanna Briggs Institute critical appraisal tools. Vote counting was used to determine the direction of associations.RESULTSOf 5276 total studies found in the search, 16 studies (12 cross-sectional, 4 longitudinal) from 11 different countries met the inclusion criteria. Seven studies examined the association between screen time and motor competence, six examined associations between time spent in sedentary behaviour with motor competence, and three papers examined the association of both screen time and time spent in sedentary behaviour with motor competence. Vote counting showed the direction of association to be predominantly negative for both screen time and time spent in habitual sedentary behaviour with the different components of motor competence. Quality of evidence ranged from 3-7 out of 9 for cross-sectional studies and 6-9 out of 12 for longitudinal studies.CONCLUSIONThere may be negative associations between time spent sedentary and motor competence in 3–4-year-olds. However, future studies with stronger study design are required to confirm these associations. Findings from this review should be considered when designing strategies and interventions to promote adherence to sedentary behaviour guidelines.