This paper addresses the subject of project management office maturity, by introducing the functions of the PMO unit, what maturity means and how it impacts performance, attempts to define a PMO maturity model, and assessment of the PMO maturity based on such models. Generally speaking, the discussion in this paper will be independent of the specific project management methodology followed by the PMO and the overall organization, since the functions of the PMO unit are the same regardless of whether the project management methodology is traditional or agile, and the standard framework adopted in the organization.This paper is published in the proceedings of the Third Edition Pan-African Project Management Conference.