This research was conducted to improve the students’ vocabulary through flashcards. This research was conducted on Wednesday, March 13th up to 27th 2019. This research used classroom action research. The participants of this research were 32 students of the eighth grade D of SMP N 1 Kebasen. This research was conducted in two cycles. Each cycle consists of planning, acting, observing and reflecting. In collecting data, the researcher used pre-test, post-test, observation sheet and interview. The mean score of pre-test in cycle 1 was 62,93 and post-test was 73,46. Meanwhile, the mean score of pre-test in cycle 2 was 88,77 and post-test was 88. Therefore, from the interview, most of the students gave good response in answering the questions. Thus, the average score reached ≥ 74 as KKM. Based on the result of the research it could be concluded that the use of flashcards in learning English could improve the students’ vocabulary.