Cindy Virginia Adella Dewantara Pengarang Rochyani Lestiyanawati.,M.Pd Dosen Pembimbing 2 Arif Widyantoro, M.Pd., B.I Dosen Pembimbing 1 Niken Kencono Ungu, M.Pd Ketua Penguji Rochyani Lestiyanawati.,M.Pd Penguji 2 Arif Widyantoro,M.Pd.B.I Penguji 1

The aims of this study are to evaluate the effectiveness of using Word Squaremedia in improving English vocabulary mastery. This study uses anexperimental research design with data collection techniques using tests, documentation, and hypothesis testing, with samples taken from class X TKR2 as the experimental class and X TKR 3 as the control class. The results ofthis study show that the learning outcomes of the experimental groupeffectively increase. In addition, from t-test, the sig.2 tailed value of 0.000indicates that there are differences between acquiring vocabulary with andwithout Word Square as a medium because the significance level was below0.05. Ha is approved whereas H0 is denied. It indicates that there is asignificant difference in the vocabulary knowledge of the first graders at SMKWiratama 45.2 Wonosobo between those who are taught without and thosewho are taught using Word Square as media. It can be concluded that WordSquare media can be used to improve vocabulary in the learning English of10thgraders students of SMK Wiratama 45.2 Wonosobo. Keywords : Word Square, Vocabulary, Learning Media.