This case study examined 10 Korean English teachers who were involved in small group work (SGW) for the purpose of improving their own English language proficiency. Their beliefs about and practices of SGW were closely observed as they actually went through a SGW. A total of 10 teachers (three groups) teaching at elementary or middle schools participated in the SGWs for one year. In the SGWs they were supposed to meet once a week in groups, give a presentation in English on a selected topic, and discuss the topics presented. Throughout the research period, they were interviewed and surveyed periodically. The result of the study showed that teachers generally had positive beliefs about SGWs and were very willing to go on with it in the same way they used to or in a little modified way. Especially, the teachers revealed strong conviction that the most powerful aspect of SGW was that it kept them motivated to continue learning, which has rarely been the case when they tried to study individually.