ENGLISH:
The purpose of this study was to determine the significant differences between eighth-grade students at SMP N 2 Puding Besar who received treatment using the Quizlet application and those who did not. How can the Quizlet application be used to improve the vocabulary mastery of eighth-grade students at SMP N 2 Puding Besar. This study used a quasi-experimental design which is part of the quantitative method. This research was conducted at SMP N 2 Puding Besar. The population of this study were VIII grade students consisting of two classes, namely VIII A and VIII B classes. The sample of this study was 62 students from both classes, namely 31 students as the experimental group and 31 students as the control group. In this study, the sampling technique that researchers used was non probability sampling more specifically using saturated sampling. Based on the results of statistical analysis of quantitative data taken from the pre-test and post-test, it was found that there was an increase in students' scores in mastering vocabulary taught using the Quizlet application method, the average pre-test was 51.16 and post-test was 77.05 in the experimental group, while in the control group students who were taught without using the Quizlet application obtained an average pre-test value of 52.32 and post-test 68.19. It can be concluded that the application of Quizlet application method is effective to improve students' vocabulary mastery.