The world around us is constantly changing. Rapidly changing world imposes new challenges, expectations and qualifications on every professional including English language teachers. in order to keep up-to-date with the rapidly evolving field of English language teaching teachers should engage in professional development activities. The current study aims to investigate English language teachers' understanding of professional development. The data for the current study were collected through questionnaires and semi-structured interviews. Results reveal that Turkish teachers of English, while displaying some involvement in professional development activities and valuing development per se, are not fully knowledgeable about it and need guidance. (C) 2013 The Authors. Published by Elsevier Ltd. Open access under CC BY-NC-ND license.