Incorporating games into learning a foreign language is an effective strategy that can lower students’ stress and improve their learning. Thus, this study tried to examine the impacts of Kahoot as a game-based learning tool on Iranian EFL learners’ vocabulary recall and retention. To this end, 50 Iranian intermediate learners were chosen for the participants of the study. After that, the participants were randomly assigned to two equal groups, one experimental and one control. Then, the participants’ English vocabulary knowledge was measured by administering a vocabulary pretest. After pretesting process, the participants in both groups received the treatment in two different ways. In the EG, the new vocabulary items were taught using the Kahoot game, while in the CG, the new ones were taught using traditional instruction. After finishing the treatment course, which lasted ten sessions, the two groups took the immediate vocabulary posttest. After three weeks, a delayed vocabulary posttest was administered to both groups to determine the effects of Kahoot on their vocabulary retention. The results of paired samples and independent samples t-tests depicted that there were significant differences between the immediate and delayed posttests of the EG and the CG in favor of the EG. The implications of this study can tell the teachers that teaching through game-based learning tools may produce better results than teaching through traditional methods. Also, the implications of this study can encourage students to practice and learn English even outside of the class context.