Using Korea Employment Panel (KEEP) I and II data, this study examined the relationship between the college admission system and educational opportunity in higher education. This study employed Random Effect models in analyzing data for three cohort from 2005, 2008, and 2018 in KEEP I and II to investigate whether the influence of socioeconomic status (SES) and private education expenditure on entering top-tiered universities differed between the transcript-based college admission system (TCA) and the exam-based college admission system (ECA). Findings showed that students from high SES families were about 1.4 to 1.76 times more likely to enter top universities. Yet, the impact of SES and the expenditure on private tutoring for the purpose of entering top-tiered universities did not significantly vary across the three cohorts, nor between TCA and ECA. This suggests that the inequality in higher education has been relatively stable over the last decade despite the adoption of a holistic college admission system. Based on these findings, I discussed the limitation of attempts to strengthen the fairness of college admissions by adjusting the ratio of TCA and ECA.