Vocabulary is one of the most important aspects of English. Therefore, 4 English skills cannot be achieved by students if they still have difficulties mastering the vocabulary. This research applied Classroom Action Research (CAR). This research deals with improving students’ vocabulary mastery. 4th-grade students at Teruna Bangsa Elementary School had problems learning English vocabulary. The researcher addressed two research questions: (1) How does the implementation of the Pictionary game improve students’ vocabulary learning? (2) To what extant the pictionary game can improve students' vocabulary learning?

This research aims to help students improve their vocabulary mastery through a Pictionary game. The researcher used 2 cycles adopted from Kemmis and Taggart that consisted of 4 steps: planning, action, observation, and reflection in each cycle. The finding of this research was that a Pictionary game could improve students’ vocabulary mastery. The evidence could be seen from the average scores of the tests in both cycles. The pre-test average score was 37,03. The post-test I average score was 75,37. The post-test II average score was 86,33.

The results of the observation and interview also showed that there was a significant improvement in students’ activeness, response, and participation. Students understood the meaning, usage, word formation, and grammar. Based on the results, it could be concluded that there was a significant improvement in students’ vocabulary mastery by using a Pictionary game. Based on the research, it is recommended that English teachers have to use a Pictionary game in teaching English vocabulary.

Keywords: classroom action research, pictionary game, vocabulary mastery.