The Human Capital Index (HCI) developed by the [World Bank, 2018a. The human capital project. World Bank. https:// hdl.handle.net/10986/30498 Accessed 26 February 2019] provides a measure which can be used to study human capital (HC) productivity gaps between countries. The HCI uses measures of survival, education and health to estimate, at a country level, the HC 'a child born today can expect to attain by her/his 18th birthday, given the risks of poor health and poor education where she lives' [World Bank, 2018a. The human capital project. World Bank. https://hdl.handle.net/10986/30498 Accessed 26 February 2019, 2]. The socioeconomic disaggregated human capital index (SES-HCI), an extension of the HCI, provides a means for analysing HC inequalities within countries. This study estimates SES-HCIs for South Africa by income quintiles, school quintiles, geographical area, gender and race. The main driver of HC inequalities in all the SES indicators is found to be the quality of schooling. Factors to address the inequalities and the limitations of the measuring instruments are identified.