The present research is conducted to provide a model to clarify critical thinking among students at Farabi Complex, University of Tehran by utilizing grounded theory. In the meantime, it was investigated how critical thinking is formed among students. The research methodology is a qualitative one based on grounded theory. Semi-structured interviews are used to gather the information while the introduced method by Straus and Corbin was utilized to analyze the information. To this end and in the first step, 25 deep interviews were conducted with students at Farabi Complex, University of Tehran. The findings from these interviews were a set of initial implications collected during the open coding process and relevant compartments were extracted. In the critical coding step, the links among these compartments were determined under such titles as causal conditions, phenomenon orientation, strategies, grounding factors, intervening conditions, and the outcomes of students’ critical thinking in the format of a critical coding paradigm. Then in the selective coding step, the trajectory of the story was drawn. In the present study, the main research compartment is raised as mental dynamism. Also, affecting casual conditions on critical thinking are divided into two general categories: individual and non-individual factors. Identified intervening factors are divided into two groups: the ambiance of accepting critics in scientific centers and the ambiance of accepting critics in society. Identified grounding factors include university rank, educational place managerial climate, and family culture. Ultimately, identified outcomes in this research include outcomes for individuals and outcomes for others.