The decline of children's opportunities to play outdoors raises a new concern about the quality of outdoor play environments, and their developmental and well-being benefits for children. This systematic review aims to synthesize the associations between outdoor play features and children's behavior and health. PRISMA guidelines were followed (2021). The inclusion criteria were studies with children aged between 5 and 12 (Population); that addressed presence, absence or disposition of equipment, natural elements, loose parts, resources availability, type of terrain and space modifications (Intervention or Exposure); in pre-post intervention or between groups (Comparison); related to health and behavior in different domains (Outcomes); with an experimental, observational, descriptive or longitudinal design (Study design). Indoor context, adult-led activities and structured activities were excluded. A literature search of five databases (PubMed, Web of Science, ERIC, Scopus, and PsycINFO) was concluded in March 2022. After identifying 28,772 records, duplicates and irrelevant titles were removed, and abstracts and full-text articles were screened in duplicate. The remaining 51 eligible articles (45 primary studies) were assessed for risk of bias with QualSyst. A narrative synthesis of the results was conducted. The most frequent behavioral or health outcome addressed was physical activity. Included studies focused on the following space features: fixed structures, space naturalness, floor markings, loose parts/equipment, area available, and the combination of factors. Although some positive effects were found, the heterogeneity between studies did not allow to draw firm conclusions on the effects of each environmental feature on primary children's health and behavior. Systematic review registration: PROSPERO CRD42020179501.