Based on the pre-research results show that the ability to understand the mathematical concepts of students VII SMPTaman Siswa Teluk Betung Bandar Lampung still low, it is important for students to have the ability to understand mathematical concepts. The purpose of this study was to determine the effect of the Flipped Classroom learning model to improve the ability to understand students' mathematical concepts. This research is a type of quasi experimental design. The population in this study were grade VII students of Taman Siswa Teluk Betung, Bandar Lampung. The sampling technique uses cluster random sampling. Cluster random sampling is the random sampling of members from the population regardless of the strata in the population. The instrument to be used in this study is an instrument in the form of a test instrument. The test is given in the form of a description item (essay) which is intended to determine the ability to understand the concepts of students in mathematics learning. The mean similarity test uses a one-way analysis of variance intended to determine whether the sample group has the same average or not statistically. To test the similarity of the average experimental class and control class, the two-party t test was used. Based on the final test hypothesis or posttest ability to understand students' mathematical concepts in the comparison material can be seen that t = 2.2617> t table = 2.0024 means that at the significance level α = 0.05 H0 is rejected, thus it can be concluded that the ability to understand mathematical concepts increases through learning with Flipped Classroom models than those using conventional learning models.