This study aims to develop a grading system for students' mathematical critical thinking based on empirical analysis and synthesis of a theoretical framework of critical thinking. The research uses a qualitative approach with a grounded theory design. The research subjects are students majoring in mathematics education in their 2nd, 4th, and 6th semesters. Data were collected through mathematical problem-solving tests, in-depth interviews, and analysis of student work documents. Data analysis was carried out through the stages of open coding, axial coding, and selective coding. The results of the study produced a model of the progression of mathematical critical thinking consisting of three main domains, namely analysis, evaluation, and synthesis. This model shows that students' critical thinking processes develop gradually, from procedural understanding to reflective and integrative thinking. The findings of this study contribute theoretically to the development of mathematical critical thinking studies and have practical implications for mathematics learning and assessment in higher education.