The purpose of this study was to determine the change in critical thinking (CT) dispositions and skills among physical therapy students over academic and clinical portions of a year and to determine correlates of change in CT abilities. Twenty-eight middle-year physical therapy students participated (26 women and 2 men; mean age, 22 years). Participants completed a descriptive survey at the beginning of the study. They also completed the California Critical Thinking Disposition Inventory (CCTDI) and the California Critical Thinking Skills Test (CCTST) before the academic year, after the academic year, and after their clinical placements. A one-way repeated measures analysis of variance was conducted on the subscales and total scores of the CCTDI and CCTST. Multiple regression was used to determine the correlations between the descriptive variables and change in total CCTDI and CCTST scores. Statistically significant improvements in all subscales and both total scores were obtained over the year. Greatest improvements on the CCTDI were observed for truth-seeking (p < 0.001) and CT self-confidence (p < 0.001). Greatest improvement on the CCTST was noted for deduction (p < 0.001). Changes in skills were more modest than changes in dispositions. None of the descriptive variables were correlated with change in total score on the CCTDI. Age was negatively associated with change on the CCTST. Although both instruments detected change over the year, more change was detected by the CCTDI; it also took less time to complete. The CCTDI can be used to monitor individual change and to evaluate the effectiveness of a program in enhancing CT ability. Although this study was conducted with physical therapy students, it should be of interest to educators in other health care disciplines because CT ability is a fundamental component of clinical reasoning.