Every nation in the globe endeavours to achieve sustainable growth in its various industries. The construction industry has an enormous contribution to the economy primarily for the developed nations experiencing urgent demands to develop and expand their infrastructure. While this expansion is taking place through projects, it is essential to find the factors affecting completion of project premium. This paper investigates the main time delay and cost overrun causes in construction projects within Oman related to clients, contractors, and consultants. Through a comprehensive literature review, reasons for delays and cost overrun are determined and a survey targeting 100 project managers was conducted to indicate top causes among them. The findings may help the government develop better policy and construction firms to modify criteria procedures to avoid such drawbacks.