This research study explored in-service teacher reflective practices. Data were collected via survey and interview to answer questions about how teachers define and engage in reflective practice, how teachers develop as reflective practitioners, and how reflective practice influences student achievement. The survey population included 170 elementary and middle level teachers in a school district in the upstate of South Carolina. Student achievement was based upon English language arts and math standardized testing data. Likert items explored the frequency, social context, and modes of reflective practice in which teachers engage. Open-response items provided teachers the opportunity to further describe practices and discuss how reflective practices are used to impact student achievement. Follow-up interviews further investigated school level practices, development of reflective practitioners, and how reflective practice is used to impact student achievement. The study was grounded in Kolb's (1984) Experiential Learning Theory and recognized adult learning occurs through continuous cycles of experience, reflection, and action. Key findings in the study indicate reflective practice as a combination of independent and collaborative processes. The study reflects some differences in the frequency of reflecting on colleagues teaching and reflecting after practice between schools with varying levels of student achievement. Data indicates teacher reflection is concerned with determining what works, what does not work, and what needs to change. Finally, the study suggests teachers develop as reflective practitioners primarily through collaboration with colleagues. The findings of this study may contribute to the body of research on reflective practice in education and teacher continuous development. [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.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]