Income gaps by gender and employment type are one of the main features of the Korean labor market, given that Korea’s income gap by gender is 31.1%, making it the highest among the OECD countries, and that the income level of temporary workers is only 72.9% of full-time workers. Doctorate holders are also affected by such discriminatory structure. An analysis of income gaps by distribution and gender among doctorate holders showed that the sticky floor effect and the glass ceiling do exist. Furthermore, an analysis of income gaps by employment type revealed that temporary workers are severely discriminated against in the labor market for doctorate holders, although discrimination was less severe in the STEM field compared to the average. A systematic and legal basis, coupled with a system for reasonable wages, is required for better treatment and to close income gaps in the labor market for those with higher levels of educational attainment.