The Olabisi Onabanjo University Library which began as a single Library at the take off of the University in 1983, is now a complex of Libraries made up of the Main Library at the Main Campus, and eight Branch Libraries. The Libraries include the Law Library, (which took off in 1987) at the Mini Campus; the Main Campus Branch Library (1997) on the Campus; the OACHS Library which initially took off at Ikenne in 1984. it later move to its current site at the Obafemi Awolowo College of Health Sciences, Sagamu in 1986, and the Sopolu Library Ikenne-Remo, which was bequeathed to the University by the Late sage and elder statesman Chief Obafemi Awolowo; the University took custody of the Library in 1989.
The other branch libraries are:
- The Faculty of Basic Medical Sciences, Ikenne
- College of Agricultural Sciences, Aiyetoro
- College of Engineering and Environmental Studies, Ibogun
- Centre for Continuing Education, Mini Campus