Flipped learning (FL) began as a local trial strategy in a US high school in 2012 and in less than 10 years has exploded in popularity, among both educational practitioners and researchers, and has now been extensively recognized and implemented at all levels of education across the world. This chapter will discuss what is known from current FL literature, what the practical implications are from this literature, what gaps exist within FL research and between FL research and practices, and how those gaps should be addressed. This chapter begins with the definition and continues discussing history and supporting theories of flipped learning and its effectiveness, affecting factors, challenges, and possible solutions from current literature. In addition, as a modified version of traditional flipped learning, a fully online flipped learning model, bichronous online learning, and HyFlex learning are introduced. This chapter concludes with future research directions.