The problem of project performance in the construction sector is a global phenomenon and Zambia's construction industry has not been spared. This work seeks to investigate the factors that are affecting project performance by local constructors in Zambia.The Iron Triangle was used as a theoretical under pinning to the work. This is so because any successful quality of a project or outcome, the project manager needs to balance between the triple constraints.The research adopted the descriptive research design because it tried to describe the actual factors affecting project performance by local constructors. Since both qualitative and quantitative data was sort, a mixed method research design was employed to be specific the convergent parallel design was used.The study concluded that for most of the project undertaken in Choma by the local constructors lack the supervision of qualified consultants attached to the project, as such there is no professional or expert advice to local constructors on the costing, timing and quality of the project.