<p>Individuals with intellectual disability (ID) face a higher risk for developing mental health problems. Recent research emphasizes the relevance of social determinants of mental health (SDOMH) in relation to this risk. This review aims to synthesize evidence on the associations between SDOMH and mental health in youth with ID, focusing on risk and protective factors across demographic, economic, social, and neighborhood domains. A systematic search of multiple databases identified 51 relevant studies, including 36 cross-sectional and 15 longitudinal studies. Using a framework-led approach, the strongest evidence emerged from the social/cultural domain (<i>n</i> = 46), followed by economic (<i>n</i> = 17), demographic (<i>n</i> = 8), and neighborhood (<i>n</i> = 1). A key finding is the substantial variability and mixed results across studies, highlighting complex, context-dependent associations. Nonetheless, some patterns emerged within the social/cultural domain. Based on both cross-sectional and longitudinal evidence, the most consistent links were found between social and cultural stressors and mental health vulnerabilities. Specifically, in families where children with ID displayed more behavioral problems, 1) parents experienced high distress or internalizing problems; 2) parenting behaviors were more negative; and 3) children faced stressful life events. The review also reveals notable research gaps, including limited attention to broader environmental and neighborhood factors, few longitudinal and multivariate studies, and minimal focus on protective factors. Future research should adopt a systematic approach, prioritize underexplored environmental and protective factors, apply longitudinal and multivariate designs to examine causal pathways, incorporate qualitative methods, and standardize measures to enable consistent analysis across studies.</p>