Atalell, K.A.Pereira, G.Duko, B.Nyadanu, S.D.Tessema, G.A.2025-10-212025-10-212025Children, 2025; 12(8):1096-1-1096-232227-90672227-9067https://hdl.handle.net/2440/147910Background: Adverse early childhood developmental outcomes across physical, cognitive, language, communication, and socioemotional domains are major global health concerns. This systematic review aimed to synthesise perinatal and childhood risk factors using a socioecological model. Methods: We searched six databases for cohort, case–control, and cross-sectional studies published between January 2000 and January 2024. Studies reporting risk factors for adverse developmental outcomes were included. Findings were organised across individual, interpersonal, community, and societal levels using a socioecological model. The protocol was registered in PROSPERO (CRD42023447352). Results: A total of 175 studies were included. Individual-level risk factors, including preterm birth, low birth weight, male sex, chronic illness, undernutrition, and excessive screen use, were associated with adverse developmental outcomes, while exclusive breastfeeding, reading books, and storytelling were protective factors. Interpersonal risks included maternal age, education, mental health, and pregnancy complications. Community and societal risks include environmental pollution, access to education, conflict, and healthcare access. Conclusions: Improving early childhood developmental outcomes may require intervention at multiple levels. Future studies may need to focus on the influence of culturally and linguistically diverse backgrounds and environmental exposures on early childhood developmental outcomes.en© 2025 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/ licenses/by/4.0/).developmental outcomes; early childhood; perinatal risk factors; systematic reviewJournal article10.3390/children12081096857916Tessema, G.A. [0000-0002-4784-8151]