The use of Project Governance Practices (PGPs) is increasingly taking a substantial stage in developing economies, particularly in a newly industrializing nation like Sri Lanka where public sector development projects have been implemented to expedite the nation's growth and prosperity. As it is essential to lay a transparent and tangible foundation for an effective public sector that can be sustained, the paper focuses on the significance of PGPs in enhancing the performance of the Sri Lankan public sector development initiatives. Structuring, normalizing, facilitating, and post-conflict-sensitive variables were used to measure the PGPs, whereas financial and non-financial performance measures were employed to evaluate the project performance. The researcher conducted direct observations and administered a comprehensive Likert-scaled questionnaire to 518 project administrators involved in various Sri Lankan public sector development projects, specifically focusing on projects related to irrigation, roads and highways, water and sanitation, and other infrastructure developmental projects. The data was analyzed using the structural equation modeling through the AMOS software. The results showed that PGPs created a considerable improvement in project performance, which increased support for expanding economic prosperity through balanced development strategies and sustainability-based policy formation.
 Keywords: Performance, Project governance practices, Public sector development projects, Sri Lanka