BackgroundOne of the most principal key aims of nursing education is to promote nursing students' and nurses' critical thinking. Therefore, nursing education needs to develop an appropriate curriculum and use effective instructional strategies for critical thinking promotion. Flipped classroom is a teaching method which substitutes individual learning for group learning in a dynamic, interactive environment where the teacher guides students to understand and use concepts. ObjectivesThe present study aimed to compare the effects of traditional lecture and flipped classroom on Iranian nursing students' critical thinking disposition. MethodsThis nonequivalent control group pretest-posttest quasi-experimental study was done in 2016 on 85 second-year bachelor's nursing students who had signed up for the Musculoskeletal Medical-Surgical Nursing theoretical training course. Because of their large number, students had been divided at the beginning of the first semester of their four-year program into two 42- and 43-student groups and attended separate theoretical training classes. These two classes were randomly allocated to either a traditional lecture or a flipped classroom group. The instructional strategies in these groups were the traditional lecture and the flipped class strategies, respectively. A demographic questionnaire and Ricketts' Critical Thinking Disposition Inventory were used for data collection. ResultsAfter the intervention, the mean scores of critical thinking disposition and its engagement domain in the flipped class group were significantly higher than the traditional lecture group (P < 0.0001). ConclusionsThis study shows the positive effects of flipped classroom on nursing students' critical thinking disposition. It is recommended that future studies assess the effects of flipped classroom on other nursing education outcomes.