Cost overruns in construction road contracts projects are a prevalent issue that hampers the successful and timely completion of infrastructure development. This study aims to analyze the factors contributing to cost overruns in road construction projects within Lusaka District, Zambia. By examining various projects and their associated cost overruns, this research identified key contributors, quantified their impact, and proposed mitigation strategies to enhance project cost management. The research employed a case study method approach, incorporating multiple sources of evidence including qualitative and quantitative to understand the scenarios. Interviews and surveys were conducted with project stakeholders, including contractors, project managers, and government officials, to gather primary data regarding project specifics and underlying causes of cost overruns. Additionally, a comprehensive review of project documentation and financial records was performed that provided quantitative insights into the extent of cost overruns. Understanding these factors would aid in the development of strategies to mitigate cost overruns, including improved project planning, risk assessment, stakeholder collaboration, and enhanced cost estimation methodologies.