This research started with the vocabulary mastery of deaf students at SDLB-B Karya Mulia II Surabaya, which was still very minimal/little so it resulted in teaching and learning activities (teaching and learning activities). The subjects of this study were all 7 students in class I which were then analyzed using a classroom-based action research design. The indicator for increasing students' vocabulary mastery was marked by an increase in mastery of vocabulary mastery by 67.5% in cycle I to 100% in cycle II through a barrier game aided by flashcard learning media. Based on the results of this study, it shows that Increasing Vocabulary Mastery Through Barrier Games Assisted by Flashcard Learning Media for Indonesian Language Subjects in Class I Deaf Children at SDLB B Karya Mulia II Surabaya is very optimal. Therefore there is a need for better development of teachers in developing students well in developing learning. ABSTRAKPenelitian ini berawal dari penguasaan kosakata yang dimiliki siswa tunarungu di SDLB-B Karya Mulia II Surabaya, masih sangat minim/sedikit sehingga berakibat dalam KBM (Kegiatan Belajar Mengajar). Subjek penelitian ini adalah semua kelas I sebanyak 7 siswa yang kemudian dianalisis dengan menggunakan rancangan penelitian tindakan kelas (classroom - based action research). Indikator peningkatan penguasaan kosakata siswa ditandai dengan adanya peningkatan ketuntasan penguasaan kosakata sebesar 67,5% pada siklus I menjadi 100% pada siklus II melalui permainan barrier game berbantuan media pembelajaran flashcard. Berdasarkan hasil penelitian ini menunjukan bahwa Peningkatan Penguasaan Kosakata Melalui Permainan Barrier Berbantuan Media Pembelajaran Flashcard Mata Pelajaran Bahasa Indonesia Pada Anak Tunarungu Kelas I di SDLB B Karya Mulia II Surabaya sangat optimal. Oleh karena itu perlu adanya pengembangan yang lebih baik pada guru dalam mengembangkan peserta didik dengan baik dalam mengembangkan pembelajaran.