The current study aimed to investigate the Curriculum Development Course knowledge levels of pre-service teachers and the depth of their reflections according to the framework proposed by Kember et al. (2000). In this explanatory mixed-method research study, pre-service teachers who enrolled in the Elementary Education-Classroom Teaching Department in two state universities of Turkey were included. The data collected through an achievement test, a reflective thinking scale, and a reflective writing form were analyzed using both descriptive and inferential statistical analysis techniques. Also, the writings of pre-service teachers were analyzed according to Hatton and Smith's (1995) framework. The results showed that taking Curriculum Development Course enriched with reflective writing activities increased pre-service teacher's course knowledge and resulted in significantly higher reflection levels in some dimensions of reflective thinking. However, there was scarcity in the number of dialogical and critical reflections. The findings were discussed and some recommendations for researchers were proposed.