This paper addresses governance of PMOs as an integration of loosely-coupled multiple governance units in large project-based organizations. A four-dimensional framework of PMO governance, consisting of structural, procedural, relational and regulative dimensions, is conceptually developed. This concept is qualitatively tested through a case study at a large European bank, which uses a network of four different project management offices (PMOs). The analysis explores the formal and informal aspects of their integration. Results suggest a predominance of relational and regulative dimensions for integration of multiple-PMO governance structures, and propose variables for observation and analysis of integration efforts in PMO governance. Implications include increased understanding of networked governance of PMOs, as well as the development of associated governance dimensions.