Keywords: Improving, Vocabulary Mastery, Duolingo Game. This research was aimed to find out the Improving Students‟ Vocabulary Mastery Use Duolingo Game. The subject of this research was a class which consisted of 20 students of class VIII SMP Darul Fikri Ngoro Jombang. The research was conducted by using Classroom Action Research (CAR) in two cycles. The instruments of the research were Duolingo tests, teacher‟s and student‟s observation sheets. In pre-test, the mean score of reading test was 59,5% and the students‟ success got 40%. In cycle 1 the mean score was 72,5% and the students‟success was 60%. The teacher‟s and the student‟s observation in cycle 1 in the first meeting got 72,73% and 66,67%, while in the second meeting got 81,82% and 83,34%. The mean score in cycle 2 was 79,25% and the student‟ success was 85%. The teacher‟s and the students‟observation in cycle 2 in the first meeting 100% and 91,67%, while in the second meeting both of the teachers‟ and students‟ observation get 100% . it meant that the criteria of minimum score and students‟success have been reached. Thus, it can be concluded that Duolingo game could improve students‟ vocabulary mastery at eighth grade students of SMP Darul Fikri Ngoro Jombang.

Warda , Unaisatul .   (2022). The Use Of Duolingo To Improve Students’ Vocabulary Mastery In Smp Darul Fikri Ngoro Jombang. IAIN Kediri