The Senate is the Legislative Branch of ASUCI, a representative body composed of elected and appointed students from each academic school. These students are elected from the Claire Trevor School of the Arts, the Charlie Dunlop School of Biological Sciences, the Paul Merage School of Business, the School of Education, the Henry Samueli School of Engineering, the School of Humanities, the Donald Bren School of Information & Computer Sciences, the Sue & Bill Gross School of Nursing, the School of Pharmacy & Pharmaceutical Sciences, the School of Physical Sciences, the Joe C. Wen School of Population & Public Health, the School of Social Ecology, the School of Social Sciences, and the student body at-large.

Starting in Fall 2016, there are now Special Interest Senators whose primary mission is the representation of and advocacy for specific groups on campus. Special Interest International and Transfer Senators shall be drawn from the international student body and the transfer student body and elected by the student body at-large. The Special Interest First Year Senator shall be drawn from the first year student body and interviewed and appointed in the Fall, with their term beginning in the Winter.

The Senate is responsible for approving the ASUCI budget for the fiscal year, approving or rejecting any legislation that is brought to them, approving or rejecting recommendations for amending the governing documents of ASUCI (such as the ASUCI Constitution), and more. The members are also responsible for meeting with the Dean of their respective schools at least once per quarter and hosting weekly office hours to address any concerns their constituents may have.

The Senate meets regularly on Tuesdays and Thursdays at 5:00 pm. All meetings are open and students are strongly encouraged to attend. Meetings are in Balboa Island B, on the fourth floor of the Student Center, or over Zoom.