Worku Mekonnen (PhD)Melaku Assefa2024-03-122024-03-122022-06https://etd.aau.edu.et/handle/123456789/2289The main purpose of this study was to assess the project planning practices and its effect on project success in Vamos Construction Company. For this purpose, descriptive and an explanatory research design with both qualitative and quantitative research approaches were applied to investigate what the current project planning practice looks like in the study organization. A total of ninety two employees working under four sites in the company were included as a sample of the study using stratified and simple random sampling method. The primary data were employed to conduct this research study. Primary data was collected through structured questionnaire. The descriptive analysis such as standard deviation, mean, frequency and percentage and inferential data analysis such as correlation and regression were performed to analyze the data. The inferential statistics such as regression and correlation analysis was performed to determine the effect of project planning on project success in the case study organization. The specific objectives are; to determine the effects of project human resource planning practices, project cost planning practices, material usage planning practices and time planning on project success of Vamos construction projects in Addis Ababa, Ethiopia. The result of this study indicates that there was a positive strong correlation between independent and dependent variables. The four independent variables (project human resource planning, project cost planning, material usage planning and time planning) contribute to forty two percent on success of construction projects as represented by the adjusted R2. Among project Material usage planning has the highest influence on the project success. Key words: Project planning, planning, successen-USThesis