<p>Construction projects play a vital role in improving socio-economic development through infrastructure provision, job creation, and facilitation of economic growth. However, delays in the implementation of these projects are a common problem that works against these benefits. In Ethiopia in general, and the Gurage zone in particular, project delays have become a significant problem that needs a careful investigation of its root causes and effective policy responses. Therefore, this study aimed to identify the determinants of project delay and assess its socioeconomic effect on project beneficiaries in the Gurage zone, of Central Ethiopia. While regression analysis and relative importance index were used to identify project delay determinants, Key informant interviews (KII) and focus group discussions (FGD) were used to assess its socioeconomic effect on project beneficiaries. Poorly defined project scope, project control, and management, an incorrect estimate of project cost and schedule, bad economic conditions, political instability, lack of construction inputs, and inadequate communication have contributed to project delays. Project delays limit transport access, and increase unemployment, migration, disputes among project stakeholders, congestion on public service delivery, and health and health-related problems. Before approving a project, the soundness of the feasibility study should be properly checked. Project monitoring, follow-up, and control should be improved as a project implementation strategy. Beyond cost and time overruns, project sponsors consider the broader social and economic implications of project delays. This study contributes valuable insights that can inform project planning and management practices to mitigate delays and maximize socio-economic benefits for project beneficiaries.</p>