This article examines the extent of the growth of temporary, casual and part-time jobs and how this has contributed to the social inequality caused by the occupational restructuring of employment in the Gauteng-City Region. It addresses the methodological problems of how to both conceptualise and measure the extent of earnings inequality caused by the growth of temporary and part-time employment in cities. The main argument is that studies that have used the concept of ‘informal sector’ to describe the growth of non-standard forms of employment do not provide us with valid estimates. Instead, we should be using concepts that accurately and directly describe the character of temporary and part-time jobs. The evidence for this study is drawn from official household surveys conducted mostly by Statistics South Africa over the period from 1993 to 2021. The results show that temporary and part-time employment in Gauteng have grown steadily over the decades and now comprise about one-third of all employment. Furthermore, part-time employment is shown to be more concentrated in low-skilled manual jobs that have low levels of unionisation.