Background: There is a need to systematically compare and contrast mortality predictors and disparities in people with intellectual disabilities (ID) for global prevention strategy development. Method: Bibliographic databases and grey literature were searched using systematic review methodology and the machine learning tool "Abstrackr." Results: Fifty-four relevant articles and reports published from 2010 to 2019 were identified. Nearly all (n = 53) were from high-income countries. Mortality disparities were apparent and consistent across countries and publication years, with no evidence of a decrease over time. People with ID can still expect to live 12-23 years less than the general population and are particularly vulnerable to deaths from respiratory infections and epilepsy. Conclusions: Both population and individual-level approaches to prevention are indicated to tackle the continuing mortality disparities in people with ID, including consideration of reasonable adjustments in general population efforts to reduce health inequalities.