This chapter gives a very preliminary definition of FI suggested by Weyrauch and Herstatt’s (2017). It is based on three criteria: substantial cost reduction compared to the cost of its conventional counterparts, a concentration of frugal product on its core functionalities, an optimised performance level indicating that FI has a certain level of technological and environmental performance. These three criteria show how FI’s innovators experiment with a new direction of technological change: more inclusive (for more people) and less rich in terms of functionalities. In order to address the issue of frugality we continue by comparing FI with other types of innovation. Some case studies of FI provide empirical illumination to the phenomenon under observation.