From 1994, the South Korean government has implemented a series of innovations to change English language education from teaching about English to developing students’ communicative competence in English. This paper discusses the impact of a teacher certification scheme, one such innovation. The scheme is examined from three perspectives: its design, implementation, and perceived future impact. The discussion draws on documents from the certification scheme, lesson plans, video-recordings, and assessment results from assessed lessons for four candidates and interviews with these teachers. Analysis of this data shows that the scheme has the potential to make future classroom practice more communicative. However, there are a number of factors which seriously inhibit the impact of this scheme and which have implications for future innovations of this type. These include ineffective communication with teachers about the innovation, teachers’ perceptions of the relevance of the promoted practice, and the degree of compatibility between the innovation and its wider educational context. Copyright © The Author 2013.