The purpose of this study was to investigate whether the flipped (revised) learning had effect on student learning outcome. Lage et al (2000) describes the flipped classroom as " Inverting the classroom means that events that have traditionally take place inside the classroom now take place outside the class and vice versa" (p.32). The participants in this study were 250 students and five teachers from a secondary school in Ardabil. Homogenous students were selected on the basis of their scores in the last year. Ten classes were considered for investigation. There were 25 students in each class and each teacher taught two classes that one of classes was flipped class and another was ordinary class. T-test was used to compare the overall performances of two classes in each subject in order to determine the effect of flipped learning on students' learning outcomes. The findings of this research demonstrated that there were significant differences between flipped and ordinary classes in students' learning outcomes.