The purpose of this study is to display the effects of the development of the pre-service teachers' reflective thinking skills to the planning, implementation and the evaluation process of teaching. Qualitative research methodology is used for this study. "Mixed Form: Experimental Design, Qualitative Data Collection and Content Analysis" which is administered in qualitative research methodology is used for this study. Case study is prefered as a research design in this framework which consists of methodology and structure of the study. The study is conducted with the 12 fourth grade students of Hacettepe University Faculty of Education Department of Classroom Teaching. Observation notes, camera recordings, interview form, self evaluation form, participant journals and lesson plans were used as a data collection tool for the evaluation of the curriculum planning. According to the findings, reflective thinking training provided positive contribution pre-service teachers' planning, implementation and the evaluation process of teaching.