Sri Lestari Ketua Penguji Lastry Forsia Penguji 1 Nirna Nirmala Penguji 1 Hery Nuraini Dosen Pembimbing 1 Shofwatun Najah Pengarang

This research is based on the problems students encounter when learning English, especially with vocabulary mastery. The writer noted that students still have problems memorizing everyday vocabulary. Therefore, the writer is interested in researching this topic. In this research, the writer used an application called Memrise. This application can help students improve their English vocabulary. The purpose of this research was to determine whether there is any improvement in English Vocabulary Mastery from the use of the Memrise Application for the tenthgrade students at SMAN 14 Kabupaten Tangerang in Academic Year 2022/2023. This research used a quantitative method with a quasi-experimental design. In collecting data, the writer used a multiple-choice test of 25 items to find out whether the students' English vocabulary has improved. In analyzing the data, the writer used SPSS 26 for the normality test with Kolmogorov Smirnov, the homogeneity test with Levene statistic and the hypothesis test with independent-samples t-test (ttest). Based on the research results obtained from the T-test, the writer found that T-count = 3.813 and Sig (2-tailed) = 0.000 < 0.05 then Ho is rejected and Ha is accepted. Therefore, the writer concluded that there is a significant effect between students' English vocabulary mastery taught by using the Memrise application.