This paper analyzed the growth of open access institutional repositories in Nigeria over the last 10 years. OpenDoar website is a directory of all open access institutional repositories in the world. It is a quality-assured global directory that enables the identification, browsing and search for repositories. OpenDoar was analyzed to get statistics of institutional repositories in Nigeria based on such parameters as: Type, Status, software, total number of records, subject covered and content uploaded. The study revealed that over the last 10 years (2009-2019) a total of 25 open access institutional repositories have been created. Findings also show that a total of 68,610 items have been uploaded in the 25 open access repositories in Nigeria since their creation till date with University of Nigeria, Nsukka having the highest upload of 23,367 items. Dspace software was found as the preferred Software for most of the repositories. The study also revealed that most of the institutional repositories are multidisciplinary. The study recommended among other things that Institutional repositories should be made a prerequisite for Nigerian Universities Commission (NUC) accreditation and funding should be made available to set up functional Institutional repositories in Nigeria