Blended, flexible, and personalized learning models are increasingly used to provide a more student-centered approach to learning. This chapter explores these models, and what current research and theory tells us about how to design these forms of learning. The aim of flexible and personalized learning is to meet the needs of student, with flexible learning focusing on how this can be done, and personalized learning on the outcomes. A common approach to implementing either flexible or personalized learning has been to use blended learning; that is, learning that occurs both online and in-person. There are many different ways in which blended learning can be implemented, with an expectation that this will continue to expand as new technologies become available. This variation in the way blended learning can be operationalized make creating universal design principles difficult. Current approaches to designing blended learning aimed at delivering flexible or personalized learning largely draw on descriptive studies of blended learning, or on theories and lessons drawn from the online and face-to-face fields. It is also common for design principles to have come from the higher education literature, where more research on the use of blended learning exists. In designing for blended learning, both the physical and online environments need considered, as do the context in which teaching and learning is to occur, the desired pedagogical approach, and what technology is available. A critical part of the design process is to ensure that learning drives the use of technology, rather than the reverse. It seems likely that blended learning will continue be used to deliver flexible and personalized learning and more investigation into how blended learning can effectively deliver flexible and personalized learning in primary and secondary schools is needed.