Children with intellectual disabilities experience unique developmental, social, and environmental challenges that intersect with adverse childhood experiences (ACEs) and positive childhood experiences (PCEs), shaping their psychosocial outcomes. While prior research has mainly examined single adversities or protective elements, the frameworks of ACEs and PCEs provide a broader understanding of their cumulative and interactive effects. However, these constructs remain underexplored in children with intellectual disabilities. This scoping review maps the range, conceptualization, and impact of ACEs, PCEs, and related concepts on psychosocial outcomes. Following the Joanna Briggs Institute (JBI) methodology, a search of PsycInfo, MEDLINE, CINAHL, Web of Science, and Google Scholar identified studies until October 2024. Two reviewers screened and extracted data using standardized criteria. Findings reveal variability in how ACEs and PCEs are defined and measured. ACE exposure, particularly the cumulative impact of multiple ACEs (polyvictimization), links to adverse psychosocial outcomes, including emotional (e.g., anxiety, depression, Post-Traumatic Stress Disorder), behavioral (e.g., aggression, conduct problems), and developmental (e.g., social and adaptive skill deficits) difficulties. PCEs—such as positive parent–child relationships, teacher–student support, and peer acceptance—mitigate risks, though impact varies by context. Intellectual disabilities severity and socioeconomic adversity shape associations. Further research is needed to inform the adaptation of ACE–PCE frameworks for children with intellectual disabilities.