Construction projects in Iraq suffer from many complex problems. Therefore, the aim of this study is to identify the most critical factors affecting the performance of Iraqi construction projects, delving into their identification, analysis, and understanding. A comprehensive list of 32 influential factors was compiled through site surveys, interviews with engineers and experts, and a review of previous research. These factors were categorized into eight groups: planning and management, design and engineering, procurement and supply chain, workforce and labor, technology and innovation, environmental and regulatory aspects, site conditions and infrastructure, and external factors. One hundred and ten questionnaires were distributed to project stakeholders, including owners, consultants, and contractors. The results found that the five most important factors affecting performance ranked using the relative importance Index are poor planning, failure to allocate resources properly, unavailability of skilled labor, poor labor productivity, and volatile economic conditions. Based on these results, for solutions to be effective, they must be adapted to the local environment. Project participants must be interested in planning as it is essential to address the same. The skills of project workers must be developed through training programs. Communication with project stakeholders must be coordinated to contribute to the decision-making process.