Background People with intellectual disabilities (ID) face barriers in cancer care contributing to poorer oncological outcomes. Yet, understanding cancer risks in the ID population remains incomplete. Aim To provide an overview of cancer incidence and cancer risk assessments in the entire ID population as well as within ID‐related disorders. Methods This systematic review examined cancer risk in the entire ID population and ID‐related disorders. We systematically searched PubMed (MEDLINE) and EMBASE for literature from January 1, 2000 to July 15, 2022 using a search strategy combining terms related to cancer, incidence, and ID. Results We found 55 articles assessing cancer risks in the ID population at large groups or in subgroups with ID‐related syndromes, indicating that overall cancer risk in the ID population is lower or comparable with that of the general population, while specific disorders (e.g., Down's syndrome) and certain genetic mutations may elevate the risk for particular cancers. Discussion The heterogeneity within the ID population challenges precise cancer risk assessment at the population level. Nonetheless, within certain subgroups, such as individuals with specific ID‐related disorders or certain genetic mutations, a more distinct pattern of varying cancer risks compared to the general population becomes apparent. Conclusion More awareness, and personalized approach in cancer screening within the ID population is necessary.