Reflective thinking is a developmental process that progresses over time from a technical, routine level to a critical, self-evaluating level. Preservice teachers, who tend to stay in the technical, routine level of critical thinking without guidance, need to be taught how to become reflective thinkers so that they are able to identify and analyze their own personal teaching practices, connect theory with practice, and understand why they are teaching. By learning to be more critically reflective in their thinking, preservice teachers will become more effective teachers, thus having a positive impact on student achievement. This dissertation research study quantitatively evaluated the written reflections of first semester preservice teachers during their first semester internship experience to determine if, after receiving explicit instruction about reflective practices, their reflective thinking abilities improved over the course of the semester. The findings in this study determined that after receiving explicit instruction on reflective thinking over the semester, 66% of the preservice teachers showed an increase in their total score suggesting that reflective thinking skills can, in fact, be taught. Although this study was explored through one specific teacher preparation program, the findings and suggestions are relevant to other programs and other state education standards. [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://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]