The purposes of this action research study were first to explore teacher perceptions of Japanese lesson study as a method of professional development, and second to take teachers through an action research process as they observed the implementation of a literacy lesson in the classroom. Situated Learning Theory, particularly related to teacher learning in the classroom setting, informed the theoretical framework. The study began with interviews with seven grade 5 English Language Arts teachers. Based on the data from the preliminary interviews, four themes emerged including: (a) influential prior educational experiences; (b) barriers to teacher professional learning; (c) effective professional development practices; and (d) concerns of Japanese lesson study. Sources of data besides the initial interviews, from the Action Research phase included, field notes of data collected from eight learning sessions that were part of the Japanese Lesson Study process, participant journals, critical incident questionnaires. Transcripts of a final interview exploring teacher learning and its effects on their perceptions of professional development and JLS in general was a final source of data. Themes emerging from the Action Research portion of the study included: (a) astounded by JLS; (b) the power of team; (c) learning in context with a peer coaching emphasis; and (d) moving to increased comfort levels. Further adding to the understanding of situated learning theory, the findings revealed the essential components of adult professional development such that teachers are influenced by the context in which they learn. This is important to consider as teacher-training sessions are often removed from the sites where they feel most comfortable. Teachers were able to overcome barriers to extended learning as a result of increased time and teacher empowerment. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]