This dissertation, "The Use of Learning Study to Enhance Teachers' Professional Development: a Case Study" by Ting-chun, Lai, 賴婷珍, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: Abstract This study aims at interpreting how the use of the learning study grounded in a learning theory, in this case the variation theory, helps enhance teachers' professional development in teaching an abstract Secondary three history topic called 'the Features of the Cold War'. It has two aims: to find out how the variation theory may be used as an effective learning theory to help teachers handle the object of learning in a feasible manner; and, to reveal to what extent the learning study could enhance teachers' professional development. In this study, a single case study was used as its research methodology. There were three teachers involved in the study. They had to work as a group and worked out a shared lesson plan for teaching the same topic with the guidance of the variation theory. After ascertaining the existing understandings of students, they had to implement and revise the lesson after each trial of teaching in the classes of 3A, 3E and 3C respectively. In order to portray the extent of impacts of the learning study on teachers' respective professional development, a multiple-source of data collection was conducted to strengthen the credibility of the study, for example, reflective journals, preparatory meetings, after lesson review meetings, teacher questionnaire and in-person interviews, etc. The study has three main findings. First, the use of the variation theory seemed to be useful as one of the effective learning theory in helping the teachers to handle the object of learning in teaching the features of the Cold War. Second, the professional development of the teachers seemed to be enhanced to a certain extent in the employment of the learning study. Third, there were limitations in the adoption of the learning study grounded in the theory of variation that might restrict the applicability of the variation theory and the extent of teachers' professional growth in particular. iii DOI: 10.5353/th_b3567092 Subjects: Experiential learning Teacher effectiveness - China - Hong Kong History - Study and teaching (Secondary) - China - Hong Kong