The implementation of Audio Visual Media in improving students’vocabulary mastery through WhatsApp Adelia Puspita 1 , Cucu Sutarsyah 2 , Burhanuddin 3 Universitas Lampung, Jl. Prof. Dr. SumantriBrojonegoro, Rajabasa, Bandar Lampung 1,2,3 1 adeliapuspita1400@gmail.com ABSTRACT This quantitative research was conducted to investigate the students’ vocabulary mastery after the implementation of audiovisual media through WhatsApp. The sample was 33 students from X MIPA 1 at SMA Muhammadiyah Bandar Lampung. This research based on the experimental group design which applied the pre-test and post-test as the instrument. Besides, the three meetings were conducted for the treatment. The data were analyzed by using Repeated Measured T-Test. The result of this research shows the mean score for the pre-test is 5.24. Meanwhile, the mean score for the post-test is 6.67. It means that the significant difference of students’ vocabulary achievement reaches out the score of 1.43 points. More specifically, the t- value > t-table shows the number of 5.452 which is higher than the t-table 2.0369. Moreover, the value of significant 2-tailed is 0.000 which can be inferred that it is lower than 0.05. Briefly, it can be inferred that the H1 is accepted and H0 is rejected. Keywords:Audio Visual Media, Vocabulary, WhatsApp, Narrative Text. I. INTRODUCTION Language holds an essential role of communication in this world. This is reasonable because language as a tool of communication allows its user to convey what is in their mind to be delivered to anyone else. Moreover, in order to communicate one to another in daily life, people surely use language to share their ideas and purpose. Besides, it is possible for people to have a different language as another people due to the difference of national language that they have. Hence, the understanding of the language spoken and written of someone is needed in order to catch a clear meaning of their intention. For this reason, language can be considered as a main point to build up the conversation amongst people. In other respect, viewed from the educational field, English as an international language become the first foreign language that taught in Indonesia as a compulsory subject. In this present time, the students have been introduced English language by the teacher since the level of kindergarten until college. It proves that learning English is really important to be learnt by the students. There are four basic skills that needed to be learnt in learning a language especially English, such as reading, writing, listening, and speaking. In the other hand, there are also some aspects that involved in learning English, such as structure, pronunciation, and vocabulary.