This research directs to know kahoot application can improve Vocabulary Mastery at tenth grade of SMK N 1 Bangsri in the Academic Year 2020/2021 and to find out how effectiveness mobile learning through kahoot application improve Vocabulary Mastery at tenth grade students of SMK N 1 Bangsri in the Academic Year 2020/2021. The researcher used true-experimental design that used pretest-posttest control design. Two classes were taken as the subjects of this research namely experimental and control class.
The data of experimental and controlled class were analyzed by using T-test formula. The result of calculation showed that in the significance degree of 0.05, the value of t-test (t0) > t-table (tt) (5.743 > 1.995). According to the criteria of the test, the result showed that there is a significance difference between students’ achievement in vocabulary mastery by using mobile learning through Kahoot application and without mobile learning through Kahoot application. It meant that mobile learning through Kahoot application is effective and applicable at the tenth grade students of SMK N 01 Bangsri towards students’ vocabulary mastery. Kahoot application could be recommended as the solution for the teachers to bring their students to a new concept of assisting the students to use their ability in mastering vocabulary.