This study evaluated the effect of high-fidelity simulation with both mannequins and live actors on flexible and reflective thinking of nursing students. Students enrolled in an undergraduate nursing program were recruited to participate in this study. Ninety students, all female, completed both pre- and post-surveys. The researchers conducted a paired samples t-test to determine if there is a statistically significant difference in students' level of flexible thinking before and after they experienced the high-fidelity simulation. Moreover, we conducted multivariate correlational analysis to examine the relationships between flexible thinking and reflective thinking. In general, statistical results in this study provide empirical support for the values of clinical simulation and debriefing on nursing students' flexible and reflective thinking. High-fidelity simulation can expose students to controlled and dynamic clinical environments, allowing them to attempt the transfer of theory to practice, learn from collaborative and active learning tasks, and be open-minded to multiple perspectives and in diverse situations. We conclude that critical reflection is an important piece of development in flexible thinking and reflective learning. During the time of post-simulation interactions, students are encouraged to reflect objectively on their performance in each scenario. The input from peers and instructors provides students with the opportunity to assess their personal ability to transfer theory to practice and evaluate if the theory design of the course is providing them with the needed information to care for the clients presented in the clinical simulation scenarios.