| This research aims to evaluate the effectiveness of implementing game-based learning method in learning vocabulary for EFL fourth graders. Participants in this research consisted of 32 grade 4 EFL students from SD Tarakanita Gading Serpong, South Tangerang, Indonesia. This research used a one-group pretest- and post-test design with the quantitative method. The “MOFIN Mystery Box” game used in this research was introduced as an interactive tool of the game-based learning method to facilitate students' vocabulary learning during one learning session. Data collection instruments in this research include a pre-test to measure students' initial vocabulary knowledge and a post- test conducted after implementing the game to evaluate their development. This game is designed to make the learning process more interesting and fun, as well as improve students' ability to master vocabulary. It is hoped that the research findings could provide insight into the effectiveness of implementing the game-based learning method with the “MOFIN Mystery Box” game as a vocabulary teaching strategy. After data analysis, the results of this study showed a positive increase in the pre-test and post-test results of students and there were no students who did not experience an increase. In other words, the use of the game-based learning method is very effective in learning English vocabulary for EFL fourth graders. |