OBJECTIVE: To examine the role of the private sector in the provision of antenatal care (ANC) across low- and middle-income countries. METHODS: Demographic and Health Survey (DHS) data from 46 countries (representing 2.6 billion people) on components of ANC given to 303 908 women aged 15-49 years for most recent birth were used. We identified 79 unique sources of care which were re-coded into home, public, private (commercial) and private (not-for-profit). Use of ANC and a quality of care index (scaled 0-1) were stratified by type of provider, region and wealth quintile. Linear regressions were used to examine the association between provider type and antenatal quality of care score. RESULTS: Across all countries, the main source of ANC was public (54%), followed by private commercial (36%) and home (5%), but there were large variations by region. Home-based ANC was associated with worse quality of care (0.2; 95% CI -0.2 to -0.19) relative to the public sector, while the private not-for-profit sector (0.03; 95% CI 0.02 to 0.04) was better. There were no differences in quality of care between public and private commercial providers. CONCLUSIONS: The market for ANC varies considerably between regions. The two largest sectors - public and private commercial - perform similarly in terms of quality of care. Future research should examine the role of the private sector in other health service domains across multiple countries and test what policies and programmes can encourage private providers to contribute to increased coverage, quality and equity of maternal care.