In the rapidly evolving landscape of online education, understanding what drives student satisfaction is crucial for designing effective learning experiences. The study examines the factors influencing English as a foreign language (EFL) students' satisfaction with online cooperative learning (CL) in massive open online courses (MOOCs). Employing a mixed-methods approach, the research investigates how different aspects of CL contribute to student satisfaction and identifies challenges students face in such environments. Quantitative data were gathered from 374 students through a structured survey, while qualitative insights were derived from semi-structured interviews with 16 participants. The findings suggest that CL enhances academic performance, engagement, and social interaction among students. However, challenges such as language barriers, unequal participation, and technological issues were also highlighted. The study emphasizes the importance of clear task assignments, effective leadership, and structured collaboration to mitigate these challenges. The research underscores the need for further exploration into the nuanced experiences of EFL students in MOOCs, particularly concerning cultural and linguistic factors that may influence their learning outcomes. These insights contribute to the broader understanding of how CL can be optimized in online education settings to enhance student satisfaction.