<p>Two important areas of professional development for teachers of English as a foreign language (EFL) in Indonesia identified in the 2003 Law on National Education System and 2005 Law on Teachers and Lecturers are disciplinary knowledge and ICT skills. The present thesis investigates institutional and individual aspects of EFL teacher professional development (TPD) in Indonesia in relation to the development of these two areas of expertise. Three studies were carried out. The first study measured Indonesian EFL teachers’ target language (English) proficiency as a core component of their professional knowledge and how it is maintained and developed by the teachers. EFL teachers’ language proficiency in this study was operationalised as their lexical, reading and writing proficiency and measured using the Vocabulary Levels Test (VLT), IELTS-like reading comprehension test and IELTS-like academic writing test, respectively. The results showed that the teachers’ length of service correlated negatively with their knowledge of academic vocabulary, as well as reading and writing proficiency, indicating issues with the outcomes of the TPD in this area. To triangulate the test results, teacher perceptions data were also gathered using questionnaires and interviews. It was found that the EFL teachers tended to overestimate their own overall English language proficiency. The second study used a longitudinal blogging activity with the EFL teachers as a form of personal professional development that targeted their English language and ICT skills while reflecting on topics related to their professional (teaching) activities. Qualitative analysis of the blog entries of three EFL teachers suggested that the individual teachers’ blogging, critical reading and reflective writing skills were very uneven. Interviews with nine teachers and 11 educational stakeholders were then conducted to understand their views on blogging as a form of professional development. The results revealed that the perceived obstacles and drawbacks outweighed the perceived benefits of blogging as a form of personal professional development. The third study examined Indonesian national TPD policy documents, how these policies were translated into local professional development programmes in Malang district. It was found that the needs for EFL teachers to maintain their English proficiency and ICT skills were only partially addressed in TPD policy and implementation. In addition, the interviewed teachers and stakeholders perceived the definitions, goals, administration, evaluation, benefits, and challenges of TPD differently. Taken as a whole, the present findings show that institutional implementation of TPD policies in Indonesia needs to better target individual EFL teachers’ English proficiency and ICT skills, and that opportunities for better professional development need to be sought at both personal and institutional levels. At the individual level, self-motivation to continue learning is crucial for English language teachers who want to keep up with change and innovation in English language teaching. At the institutional level, needs analyses and environmental analyses are essential in designing programs for maintaining and developing teacher professional competency.</p>