Motivation, a major contributor to the acquisition of language skills, can be promoted consciously through principled methods. This study investigated the impact of cooperative learning (CL) on foreign language (FL) learners' motivation in Iran. Both quantitative and qualitative measures were applied to pursue the aims of this study. The participants were 180 male and female intermediate FL learners in three groups. The Experimental Group 1 (N = 60) received two CL techniques: Student Teams-Achievement Division and Cooperative Integrated Reading and Composition (CIRC). The participants in Experimental Group 2 (N = 60) received Round-Table and Think-Pair-Share techniques. The participants in the Control Group (N = 60) were taught the same materials conventionally without any CL strategies. The Language Learning Orientations Scale (LLOS-IEA) was used before and after the intervention to track changes in FL learners' motivation. The results indicated that the integration of CL techniques into FL classrooms had a significant impact on FL learners' motivation in both experimental groups. The post-hoc Tukey's Test also depicted no statistically significant difference between the two experimental groups after the intervention. The results of Kruskal-Wallis test comparing the three groups in subscales of LLOS also revealed that all subscales--amotivation, intrinsic (Knowledge, Accomplishment, and Stimulation) and extrinsic (External Regulation, Introjected Regulation, and Identified Regulation) motivation--were statistically significant. In addition, the analysis of the qualitative data revealed some cultural and contextual constraints associated with Iranian context.