Companies invest in project management disciplines to add value, advance strategies, and increase competitive advantage. Mature organizations are adding Project Management Offices (PMO) to provide additional support to increase the likelihood of project success. If PMO’s are the solution to the problem, then why are the outcomes still problematic? We seek to address this research question by utilizing social capital theory to theorize on the impacts of PMO social capital on PMO performance. Further, we delineate the impacts of PMO characteristics on social capital and the moderating role of PMO culture on performance. This study seeks to extend the existing project management literature and has significant implications for research and practice.