The current study tried to investigate the impact of cooperative learning (CL) on improving Iranian intermediate EFL learners' oral proficiency motivations toward learning English. To fulfil this objective, 90 participants were selected and divided into two equal groups; one experimental and one control group. Then, the sample's speaking skills were first examined through an English oral test prior to and after some cooperative learning instructional activities were provided. Next, a seven-point Likert scale-questionnaire was administered to the participants before and at the end of the course to check students' motivations towards the use of cooperative learning in English classes. After analyzing the data, the results indicated a significant improvement in the learners' speaking skills after utilizing cooperative learning techniques. Furthermore, results proposed remarkable differences in favor of cooperative learning in enhancing intrinsic motivation, but no differences were observed on other sorts of motivation. The researchers suggested using CL in English classes might be beneficial for teachers, which may in turn progress students' speaking skills and motivations.