Background: Population studies confirm mothers with intellectual disability have poorer antenatal outcomes than other mothers but less is known about any differences in sociodemographic characteristics between these groups. Method: A systematic review of population-level studies on parents with intellectual disability was undertaken from January to August 2023. Seven electronic databases and references from two literature reviews were examined and 27 studies met inclusion criteria for the review. Results: All studies reported on mothers and only one on fathers. Maternal age and socioeconomic status were most frequently reported; age in 26 studies and socioeconomic status in 23 studies. Most studies found mothers with intellectual disability were significantly younger (73%) and more disadvantaged (83%) than their peers. Conclusions: Maternal intellectual disability co-occurs with established parenting risk factors in the general population. Social welfare programs must become disability-inclusive and population datasets should routinely include disability items. A knowledge gap remains in relation to fathers with intellectual disability.