Objective: The implementation of internal quality assurance in higher education faces many obstacles. This research is focused on the obstacles of implementing the internal quality assurance system in Private higher education. Internal quality assurance system is a system carried out by universities independently. Method: The approach used in this research is qualitative with case study method. The case studied is the obstacle to the implementation of internal quality assurance system. Data collection uses combining an internal document review with semi-structured interviews. The qualitative interview data were subject to thematic analysis, a method for systematically identifying, organizing, and offering insight into patterns of meaning across a dataset. Result: In terms of administrative obstacles, it was found that the internal quality assurance agency at Puangrimaggalatung University only had 62.5% of standard documents. The organizational constraints found include 1) Limited understanding of internal quality assurance system only for structural officials, not for all but not for all stake holders in tertiary institutions. 2) Difficulties in determining measurable indicators of successful implementation of the internal quality assurance system, and 3) Unclear responsibilities among various structural positions resulting in overlapping of authority, which complicates internal quality assurance system implementation. In terms of psychological constraints, data is obtained in the form of neglect, disdain or cynical attitude towards quality assurance systems and processes. Conclusion: Based on an in-depth study of the data that has been collected, it is concluded that the implementation of the internal quality assurance system at private universities is going well however. there are obstacles in 3 areas, namely 1) Administrative obstacles 2) organizational obstacles and 3) psychological obstacles.