This paper identified and assessed the importance of project management (PM) competencies of indigenous uilding construction firms (BCFs) in the Upper West region of Ghana. It also analyzed the relationships between the PM competency groups. Empirical evidence on 12 key PM competency groups were decoupled into 42 sub-groups. These were identified and ranked in order of importance to project success of the 44 BCFs. A structural equation model was used to assess the causal relationship between the 12 PM competencies. The findings indicate that of the 12 PM competencies, project cost management, project risk management, and project quality management emerged as the most important to the success of a project. Again, there was a strong positive relationships between and among all the 12 PM competencies. The study argues that the findings could serve as a guide for the local BCFs in their future professional training and development programs.