Background: Four skills in English language are reading, listening, speaking and writing. Components in English language are grammar, vocabulary and pronunciation. Small Group Discussion is one of academic program in School of Dentistry UMY, which divided into two classes, there are English and Bahasa class. Small group discussion in English class is an activity which students do asking and answering, summarize journal in English and looking for answer of questions in previous meeting that haven’t answered yet. Indirectly, small group discussion can help students in English language skills. Objective: The aim of this study is to find out the differences of student’s English ability before and after attending small group discussion in English class at School of Dentistry Universitas Muhammadiyah Yogyakarta. Method: This is an analytic descriptive analitic study with all of English class small group discussion students in dentistry UMY as a sample. The method is take pre test data in the beginning and at the end of small group discussion on block that are chosen. Questions in this study consist of 20 questions, which divided into 10 questions for vocabulary and grammar. Result: The result showed that there are differences in student’s ability before and after attending small group discussion in English class. Data analyzed with paired t test shown that there are significant differences. Conclusion: There are differences which is enhancement of student’s ability before and after attending small group discussion in English class