Although previous studies have highlighted the positive effects of cooperative learning (CL) on academic achievement as well as the learning environment, they have not shown how this happens. The purpose of this study was to determine the effectiveness of CL in the field of nursing, as well as to identify students' perceptions of how these effects occur. In this mixed methods, sequential explanatory design data were collected through achievement test, WIHIC questionnaire, and in-depth interviews. There was a significant difference between the academic achievement of students and also their perception of classroom environment in the experimental and control groups in favor of CL. The students' experience indicated that CL not only creates a secure environment and enhances the deep learning and motivational process, but also increases instructor support and provides equal opportunities for student involvement in the patient education classroom. The findings of this study illuminated the role of social interdependence theory played in helping students connected with each other to promote learning. This study can increase the willingness of instructors to implement CL. It encourages administrators to meet the prerequisites for implementing CL.