This chapter introduces the notion of open innovation, which is about organisations making use of external ideas, solutions, and technologies instead of only relying on its internal innovation. Three different forms of open innovation are discussed: inside-out, outside-in, and coupled innovation, which differ with regard to the direction of the idea flows. The chapter also introduces a number of models for open innovation, including crowdsourcing, product platforming, collaborative innovation networks, and innovation contests. Digital innovation has transformed many businesses, enabling new kinds of smart, connected products as well as novel business models based on platforms.