The characteristic of a project is different with the operational process, therefore the role of a leader in the project is also different. The researchers of project management have examined the role of project leaders in project success. The results of those studies are still very diverse. Some researchers say that there is a strong correlation between the two, but some say that there is no significant direct link between leadership and the success of the project. The meta-analysis study is conducted to obtain a comprehensive overview of the previous studies to clarify the different opinions. Based on the exploration of 115 cases of research from 36 project management studies, it is found that between leadership and project success has low direct correlation. This situation happens because contextual factors of project type and the country of project location influence the role and style of leadership in the success of the project.