MARIA KARMELITA Pengarang SELFIANA P MBADI Dosen Pembimbing 2 Alexander Home Kabelen Dosen Pembimbing 1 Alexander Home Kabelen Penguji 1 Gracia M. N. Otta Ketua Penguji SELFIANA P MBADI Penguji 2

This research is entitled “The Effect of Using Wordwall in developing vocabulary of the 10th grade students of SMAN 4 kupang in the Academic Year 2024/2025”. The aim of this study was to find out the effect of using Wordwall game to vocabulary mastery of the tenth students of SMAN 4 Kupang, in academic year 2024/2025. The problem of this research was; What is the effect of using Wordwall game in developing vocabulary of the 10th grade students of SMAN 4 Kupang?. The method used was quantitative in experimental design. The population of this research was 427 students of 10th grade students of SMAN 4 Kepang. The researcher took 10% of the population (42 students) as the sample. This sample was divided into 2 classes: Class XD as an experiment class and Class XE as a control class which each class consists of 21 students. the instrument used was a multiple-choice test that consisted of 25 items. Iin collecting the data the researcher used pre-test, treatment (only for experiment class), and post-test. The data were analyzed by using SPSS that consists of test of normality, test of homogeneity, test of Mann-Whitney and test of hypothesis. The results show that was a positive effect of using Wordwall in increasing students’ vocabulary, because the result of students’ scores of experiment class is 78,67 while the control class is 53,62. The p-value (asymp. Sig 2-tailed) is 0,000 and it’s lower than the level of significance 5% (0,000 < 0,05). It can be concluded that the null hypothesis (H_(0 )) is rejected and the alternative hypothesis (H_(a )) is accepted. It means there is an effect of using Wordwall to improve student’s Vocabulary. Key terms: Improve, Using, Vocabulary, Wordwal.