In this study, we investigated the effects of teaching critical-thinking principles on university students' epistemological beliefs, whether these effects had any relation to the teaching approaches, and whether there was any significant interaction effect between teaching approach and students' epistemological beliefs. One hundred and eight undergraduates were randomly assigned to three different 65-min instructional interventions, namely, General, Infusion, and Immersion approaches. Statistical analyses of the data using a Repeated Measures ANOVA showed a statistically significant higher post-assessment performance, F (1,105)=19.769, p=.00. The main effect related to the intervention was also significant, F (2,105)=3.995, p=.021, but there was no significant interaction between intervention and epistemological beliefs. Post hoc comparisons revealed that students assigned to the Infusion strategy outperformed those assigned to the General approach on epistemological change.