Abstract: Digital nudging is omnipresent in users' daily lives and constantly influences decisions in digital choice environments that require users to make decisions such as web-based forms or mobile apps. It uses interface design elements and aims to guide users' behavior in specific directions. So far, there is quite a lot of research in that stream, whereby each article focuses on one specific context in which digital nudging is applied. To assist researchers and practitioners that aim to study or design information systems, we provide an overview of existent research in that stream. Following the grounded-theory method, we categorize 88 publications and reveal ten forms and five contexts of digital nudging. We also provide an overview of relationships between forms of digital nudging and their contexts. Our findings contribute to digital nudging research by offering an in-depth and structured overview of existing research and future research directions.