The ASPSU Student Senate is the legislative branch of student governance at Portland State University. The Senate is responsible for approving the Student Fee budget, confirming appointments, Constitutional revisions, the ASPSU budget, and any ASPSU bylaws and guidelines. In addition, the Senate also has several sub-committees designed to meet and connect the various needs and activities on campus to the main senate body.

The Senate consists of 25 voting members and 3 non-voting members. The voting members consist of One representative from each of the Student Activities and Leadership Programs (SALP) clusters, At-Large representatives, one graduate class representative, and three freshman class representatives. Most of the senators are elected during the student elections. Others are appointed by the President.

The Senate meets at least twice monthly during the academic year and presided by the Vice-President.