This study validated the Critical Thinking Disposition Scale (CTDS) and examined predictors of critical thinking among Vietnamese pharmacy students. A cross-sectional study of 833 students used a validated instrument, with Confirmatory Factor Analysis confirming a robust two-factor structure (CFI = 0.968, RMSEA = 0.068). Students showed a moderate overall disposition (M = 33.81, SD = 4.51), with higher Reflective Skepticism than Critical Openness. Bayesian Model Averaging and regression identified fifth-year status and enjoyment of pharmacy studies as statistically significant correlates within the evaluated dataset (R² = 3.91%). Fifth-year students scored significantly higher (p < 0.001), whereas fourth-year students did not differ from third-year students. GPA and gender were not significant predictors. The findings suggested that intensive experiential clinical learning in the final year may foster critical thinking development. Earlier integration of active learning and clinical simulation may help reduce developmental gaps and promote more balanced critical thinking profiles.