This research was aimed at determining the use of Prezi in improving students’ grammar mastery. The research method was Classroom Action Research (CAR), which consisted of 2 cycles, each cycle including planning, implementing, observing, and reflecting. The data collection was pre-test and post-test. The result showed students’ increased learning outcomes in each cycle. The increase in learning was shown in the pre-test result with a percentage of learning completeness of 0%, and there was an increase in the post-test cycle from 1 to 59%, and it increased again in the results of the post-test cycle from 2 to 82%. The increase in learning outcomes from pre-test, post-test 1, and post-test 2 was due to improvements in the application of Prezi. It can be concluded that learning using Prezi in Grade IX SMP Plus Abdul Aziz can improve students’ grammar mastery.