This study aimed to investigate the impact of role-play on the vocabulary learning and retention of Iranian intermediate-level EFL learners. A quasi-experimental design with a pretest-posttest control group was employed to achieve this objective. The study consisted of 50 male intermediate students who were conveniently selected as participants. The research instruments included an Oxford Placement Test (OPT), a pretest, an immediate posttest, and a delayed posttest. During the treatment period, the experimental and control groups attended 12 classes at the institute. The conditions were identical for both groups, except that role-play was incorporated into the instructional approach for the experimental group while it was omitted for the control group. The findings indicated that role-play positively and significantly influenced the learners’ vocabulary acquisition and long-term retention.