Abstract Background Adverse Childhood Experiences (ACEs) have garnered attention globally for their detrimental effects on children’s development, such as lower communication, gross and fine motor, and personal-social domains. While extensively studied in high-income countries, there remains a gap in understanding their prevalence and impact in low- and middle-income countries (LMICs). This review aimed to identify, evaluate, and summarize the findings of an association between ACEs and children’s developmental and mental health outcomes in South America Methods A systematic review was conducted to investigate the association between ACEs and childhood development in South America. Databases MEDLINE, PsycINFO, Web of Science, Applied Social Sciences Index and Abstracts, Literatura Latino Americana em Ciências da Saúde, IBECS and CINAHL were searched. Selection criteria encompassed studies from Brazil, Colombia, Argentina, Peru, Venezuela, Chile, Ecuador, Bolivia, Paraguay, Uruguay, Guyana and Suriname examining the effects of ACEs on developmental outcomes and mental health disorders in children under 18 years old. Quality assessment aligned with World Health Organization standards was employed. Results Twenty-four studies met the inclusion criteria, with most categorized as low or very low quality. While the majority demonstrated a significant association between ACEs and developmental or mental health outcomes, a few studies reported null findings. Challenges in study quality, such as small sample sizes and selection bias, were identified. Conclusions Despite limitations in study quality, findings underscore the impact of ACEs on child development and mental health in South America. Because of the low quality of the existent studies the next steps should be to grasp a greater understanding of the issue. This review also highlights the urgency for further research and targeted interventions to mitigate the long-term consequences of ACEs in this region. Key messages • ACEs profoundly affect child development and mental health in South America, necessitating urgent attention and intervention. • Addressing the impact of ACEs in South America is critical for fostering healthier developmental trajectories and enhancing public health outcomes.