University campuses (including college campuses) are home to many ecologists and conservationists, resulting in a large number of studies on campus plant and animal taxa. However, a systematic review on the biodiversity of university campuses is still lacking. We conducted a comprehensive review covering the history, diversity and distribution patterns of living biodiversity on university campuses globally. We found over 300 university campuses that conducted biodiversity surveys, mostly on plants and birds, with China and India as research hotspots. These university campuses harboured high biodiversity, with an average of 199 plant species and 66 bird species on each campus, including many endemic and endangered species. Hence, university campuses provide a unique opportunity for urban biodiversity research, conservation and education, as well as connecting the public with nature through citizen science.