The student union facility is a building found on college and university campuses that provides numerous services to students, faculty, staff, and other members of the campus community. The purpose of a student union is to support co-curricular activities that will increase student engagement by serving as a gathering space for students. While the student union is also known as the student center, student commons, or simply unions, it is often referred to as the living room of campus because of its versatility in providing opportunities for community building among students. This entry provides an overview of student union facilities at institutions of higher education, then explores their origins, expansion, relationship to social justice, and their contemporary professionalization and standardization.