Reflection involves taking the time to deeply consider a past situation and examine areas of weakness or confusion. It allows identification of learning needs and the development of an action plan to improve future experiences. The aim of this study was to assess second-year dental students' ability to reflect in writing on a clinical rotation when prompted with a guided reflection template. The 76 second-year dental students enrolled in a periodontics clinical rotation course at one U.S. dental school in 2016-17 completed two reflective writing exercises during the semester. A total of 144 journals (after excluding incomplete journals) were analyzed individually by two evaluators following a rubric developed by Kember. This rubric combined Mezirow's seven levels of reflection into four categories: Habitual Action (HA), Understanding (U), Reflection (R), and Critical Reflection (CR). The first two categories are examples of non-reflective thoughts, and the latter two are reflective. The two sets of journals were also compared. On average, the journals contained 0.2% HA, 15.9% U, 73.8% R, and 10.1% CR, averaging 16.1% non-reflective thoughts and 83.9% reflective thoughts. Comparison of the students' first journal submissions to their second showed that the first journals averaged a higher percentage of reflective thought than the second journals: 85.2% vs. 82.7%, respectively. However, the first journals showed a lower average percentage of critical reflection than the second journals: 9.3% vs. 11.3%, respectively. Overall, a high degree of reflection was found in these students' journals after rotation in periodontics clinic, suggesting that reflective journaling can serve as a useful learning exercise to promote continual improvement during clinical training.Erin N. Schwoegl, BS, is a Class of 2021 DMD student,