This research aims to find the differences between vocabulary mastery taught with and without kahoot and to examine the effect of kahoot as a media in improving the student’s vocabulary at eleventh-grade students of MA Darul Ulum Purwogondo in the academic year 2021/2022. A quasi experimental research was used in this research. The population in this research were the eleventh grade students of MA Darul Ulum Purwogondo consisted of 116 students. The sample was 59 students which were taken in XI Science and XI Social 1 by using purposive sampling. The data was collected by giving multiple choice test. The calculation was done by using SPSS 25. Based on the data analysis, the result of this research showed that Ha (alternative hypothesis) was accepted and H0 (null hypothesis) was rejected. It could be seen from the mean score in post-test. The mean score in experimental class was 82 while control class got 76. Then, the result of t-test in this research showed that the value of ttest > ttable (4.040 > 1.672). So, it can be concluded that Kahoot as a media has significant improve and positive effect to improve student’s vocabulary mastery.