Cultural differences should be considered as a main strategic issue when forming and managing international strategic alliances, especially for the alliances that are formed of members who have huge cultural differences like Renault-Nissan alliance. This paper focuses on studying the cultural impacts on the international strategic alliances through analyzing Renault-Nissan case; whereby trying to prove that the cultural differences are not obstacles in front of the international strategic alliances if well managed. On contrast, the cultural differences may provide new opportunities by combining the best of the different cultures and come up with new best practices like what Renault and Nissan has done. The first part of this paper provides an introduction about international strategic alliance, its definition and characteristics based on the Organization for Economic Co-operation and Development (OECD), and the main benefits companies aim from strategic alliances in general. The second part provides an overview of Renault-Nissan alliance and a brief description about Nissan revival plan which was developed by Carlos Ghosn, in addition to the synergies of the alliance. The third part provides a description of the new cultural environment of the alliance and compares the main cultural differences or challenges that should be considered in managing this alliance like individualism vs collectivism, power distance, masculinity vs femininity, uncertainty avoidance, time perception, truth vs virtue, decision making, language and enterprise loyalty. The fourth part provides details and figures that show the alliance success and the benefits it has gained for both Renault and Nissan as their alliance became the fourth car manufacturer on the global level. The fifth part as being the conclusion confirms that Renault-Nissan alliance success is evidence that the huge cultural differences between the allied companies are not obstacles for international strategic alliances.