PurposeProject managers' competencies contribute toward project success in a considerable manner. The significance of technical competencies' (TCs) contribution toward success in Oil and Gas (O&G) projects is even higher due to the complexity and the technology-intensive nature of these projects. However, technical competencies have often been overlooked in favor of behavioral competencies or simply identified and listed in terms of their significance. Thus, there is currently very limited research-based knowledge concerning the contribution mechanisms of technical competencies toward project execution success. Hence, the aim of this study is to explore the contribution mechanisms of TCs toward success in O&G projects.Design/methodology/approachA case study was employed as the research strategy through which data was collected from project professionals in O&G projects in the Kingdom of Bahrain using semi-structured interviews. Transcripts of the interviews were then analyzed through thematic analysis method with the aid of NVIVO 12.FindingsThe findings reveal six mechanisms through which technical competencies of project managers contribute toward execution success in O&G projects. TCs not only act as a launch pad toward project success, but also help in optimizing engineering designs throughout the project life cycle.Originality/valueInstead of simply identifying and listing TCs, the obtained results enhance our current understanding of their contribution mechanisms toward project success in O&G projects.