Technological learning and the drive to self-sufficiency in different industries emphasize the role of companies in the knowledge acquisition from external sources. Iran's petroleum industry is also a suitable case to study in this area, given the large firms on the one hand and the long-term historical partnerships with foreign companies on the other. Some of the industry's achievements, such as sustainability under sanctions, the country's largest source of export and some recent breakthroughs, particularly in the registration of international patents and localization of various technologies, show the success of learning efforts. This study, which examines the learning processes to joint R&D (JRD) PROJECTS in the petroleum industry, analyzes the path of technological learning in this industry using a mixed method approach and multi case study method. For this purpose, four successful JRD PROJECTS in technological learning in upstream and downstream are selected and 16 interviews are conducted with project managers and experts of selected PROJECTS and using the JRD's life cycle to present a technological learning model in JRDs. The results of theme analysis of interviews show that the most important and effective component of the model is "effective factors". The most affected component is "types of learning". Also, the most effective factors and the most effective learning mechanism are "absorption capability", "cultural homogeneity" and "learning by interacting" Respectively.