Using nationally representative household survey data from 1995 to 2006, this paper explores heterogeneity among female part-time wage (salaried) workers in post-apartheid South Africa, specifically distinguishing between individuals who choose to work part-time and part-time workers who report wanting to work longer hours. As in studies of voluntary and involuntary part-time employment in other countries, the findings show that involuntary part-time workers in South Africa are outnumbered by voluntary part-time workers. In contrast to other countries, however, involuntary underemployment in South Africa has not risen substantially over time, nor is there consistent evidence to suggest a positive correlation between involuntary underemployment and broad unemployment. Significant differences are found among part-time workers, with occupational characteristics specifically being identified as key correlates of involuntary part-time employment. The wage premium to female part-time employment in South Africa, identified in an earlier study, is shown to be robust also to a distinction among part-time workers, and involuntary part-time workers are found to have a stronger labour force attachment than women who choose to work part-time.