The contribution of ISO 9001 certification to organizational performance is a classic topic in the literature. However, they are only rare studies that have explored the relationships between contingency factors of ISO 9001 certification, effective implementation of quality management system and organizational performance in manufacturing companies. In the Moroccan context, this research problem hasn’t been previously investigated, thus, a qualitative design is adopted in order to develop a deep understanding of it. 8 semi-structured interviews were realized with quality managers operating in different branches of the industrial sector in Morocco; secondary data were also included. Unlike the traditional model of internal and external motivations for ISO 9001 certification presented by many authors, the findings reveal the following two main characters of the contingency factors of ISO 9001 certification: commercial and managerial. The themes of the contingency factors for certification that have a commercial nature don’t explain the effective implementation of quality management system, consequently, little results emerge from gaining ISO 9001 certification. But, the themes of the contingency factors for certification that have commercial and managerial natures, specifically the last one, lead to the effective implementation of quality management system, as a result, major benefits are achieved. Also, it is worth nothing that the relationships between effective implementation of quality management system and themes of organizational performance that have emerged from data analysis are both direct and indirect, which in turn arguments the importance of the managerial nature of reasons for pursuing ISO 9001 certification.