ABSTRAK

The main objective of the research is to find out the purposes of English teachers to engage in Teacher Professional Development (TPD), methods done by them in developing professionalism, and impact of TPD towards their teaching performance.
The design of the research was case study. This research was conducted at Two Junior high schools and one senior high school in Bandar Lampung. The subjects of this research were five English teachers of the schools who were chosen by Purposive sampling. They were chosen based on their teaching experiences rang between one to more than ten years teaching experience.
The main techniques to get the data in this research were interview, document analysis and observation. Observation was conducted to their teaching activities. Interview was also employed to the teachers to achieve the trustworthiness of the data. The researcher then analyzed the document related to lesson plan and other document related to their teaching activities. The data were then analyzed using the model proposed by Cresswell consisting of organizing and preparing data for analysis, reading through all data, coding the data, interrelating themes/description, and interpreting the meaning of themes/description.
Referring to  the results  of the analyses,  it can  be concluded that:  (1) English teachers have two main purposes in engaging to TPD, they are to develop their qualities and to improve students’ achievement; (2) The methods varied among the teachers in developing their professionalism. Nonetheless, MGMP and workshop are the methods that mostly done by them; (3) TPD has positive impact on their teaching performances.
Based on the research findings, it can be concluded that in general, the main purposes of engaging in TPD were to improve their quality and to promote students’ achievement, the methods mostly done by teachers in developing professionalism were MGMP and workshop, and TPD has positive impacts on
English teachers’ teaching performance. However, it can be said that the more teaching experience the teachers have, the more methods they did in developing professionalism  and  the  better impact  of TPD towards teaching performance. Thus, teachers are suggested to actively participate in TPD.

Keywords: TPD, Purpose, Method, Impact, Teaching Performance