The purpose of the present study is twofold: (1) to investigate the relationship between the efficacy of teachers of English as a foreign language (EFL) and their self-reported practice of communicative language teaching (CLT) and (2) to examine the impact of an in-service teacher education program on teachers' efficacy and self-reported and actual practice of CLT. Data came from a Teachers' Background Questionnaire, English Teachers' Sense of Efficacy Scale (Chacon, 2005), Communicative Orientation of Language Teaching (COLT; Spada & Frönlich, 1995), and the questionnaire version of COLT. Fifty Turkish EFL teachers working in eight schools responded to the questionnaires, and 20 of them were observed. The findings indicate that after the in-service education program, the teachers not only improved their practice of CLT but also became more efficacious. The findings highlight the importance of awareness-raising activities for professional development programs as well as the need for multiple instruments to analyse the extent to which teachers' self-reported beliefs and practices concur with their observed teaching practice.