The gathering, which was organized by the school's reformist Islamic Council, was delayed by students for two days in an effort to prevent clashes with security forces.
One participant at the gathering told Radio Farda that as soon as the event began, security agents from the university "tried to disperse the students by taking away loudspeakers, which eventually led to some physical clashes."
The student, who requested anonymity for security reasons, said that demonstrators protested the policies of "President Mahmud Ahmadinejad, the supreme leadership in Iran that does not accept criticism, the clampdowns on the political activities of university students, and the banning of [student] publications."
The student added that the gathering continued despite the heavy presence of security agents.
The Reformist Students of Tehran held their gathering earlier on December 7, during which slogans such as "down with the dictator" were chanted concerning Ahmadinejad's policies.
Students Day in Iran commemorates the deaths of three students killed in clashes with the police in the 1950s. It has become an annual event during which liberal-minded students protest against government policies they view as restrictive.