The aim of this paper is to first of all determine, and later to explain the cause-and-effect relationship between culture and strategic leadership, as well as their influence on the results of international development projects (ID). In the first segment of the paper, we will explain the concept of international development projects and how they differ from profit projects. Then we will explain the differences between leaders and managers, in order to define as precisely as possible the functions and tasks that leaders have in the implementation of projects. We will also explain why it is important for the success of projects for leaders to understand different cultures. By considering at all these factors, with the help of the developed model, presented in this paper, we will show how culture affects the choice of leadership strategy and how it affects the critical success factors (KFU) as well as the outcome of international development projects.