Private-sector providers are increasingly being recognized as important contributors to the delivery of healthcare. Countries with high disease burdens and limited public-sector resources are considering using the private sector to achieve universal health coverage. However, evidence for the technical quality of private-sector care is lacking. This study assesses the technical quality of maternal healthcare during delivery in public- and private-sector facilities in resource-limited settings, from a systems and programmatic perspective. A summary index (the skilled attendance index, SAI), was used. Two-staged cluster sampling with stratification was used to select representative samples of case records in public- and private-sector facilities in Enugu and Lagos States, Nigeria. Information to assess criteria was extracted, and the SAI calculated. Linear regression models examined the relationship between SAI and the private and public sectors, controlling for confounders. The median SAI was 54.8% in Enugu and 85.7% in Lagos. The private for-profit sector’s SAI was lower than and the private not-for-profit sector’s SAI was higher than the public sector in Enugu [coefficient = –3.6 (P = 0.018) and 12.6 (P < 0.001), respectively]. In Lagos, the private for-profit sector’s SAI was higher and the private not-for-profit sector’s SAI was lower than the public sector [3.71 (P = 0.005) and –3.92 (P < 0.001)]. Results indicate that the technical quality of private for-profit providers’ care was poorer than public providers where the public provision of care was weak, while private for-profit facilities provided better technical quality care than public facilities where the public sector was strong and there was a relatively strong regulatory body. Our findings raise important considerations relating to the quality of maternity care, the public–private mix and needs for regulation in global efforts to achieve universal healthcare.