Productive Subjects of Object Oriented Programming have the 2nd densest learning hours after web programming. For this reason, 21st century learning models and approaches are needed that are able to overcome the complexity of these subjects. From these conditions the Flipped Classroom model is one of the 21st century learning models that can be used in PBO subjects. Because in this model, students have broad flexibility to study learning materials independently, make a list of questions, before being discussed in school (concepted). The type of research in this study is a quasi-experimental research with a quantitative approach. The results of the study stated that the flipped classroom model could improve student learning outcomes.