Learning study has been used to enhance teacher professional development in many cities and countries all over the world, including Hong Kong, Sweden, United Kingdom, Singapore and Brunei. Since Learning Study has been regarded as an effective approach for teacher professional development, it was introduced as a core course in the training programmes for pre-service teachers in the Hong Kong Institute of Education in 2007. This paper explores the impact of learning study on pre-service teacher professional development by looking into an English language learning study conducted by a group of pre-service teachers in Hong Kong. It reports how the pre-service teachers learned to teach via participating in Learning Study and discusses what challenges they had encountered in the process. The paper concludes with implications on the further development of learning study and its application in educational programmes for pre- service teachers.