An important part of the University experience is participation in an active, democratically governed student union. It is through the unions that student views are represented on all the major university committees, particularly regarding the academic and social life of the students. There are five student unions at TUC as well as an interdepartmental Student Union.
The union council members are elected once a year by all the students who are enrolled in the unions through cross campus elections held on a date set by the Hellenic Association of Student unions. Graduate students have their own association union council members represent their fellow students in the Senate, the Council of TUC and the Schools' General Assembly meetings.