Online extremism remains a persistent problem despite the best efforts of governments, tech companies and civil society. Digital technologies can induce group polarization to promote extremism and cause substantial changes to extremism (e.g., create new forms of extremism, types of threats or radicalization approaches). Current methods to counter extremism induce undesirable side‐effects (e.g., ostracize minorities, inadvertently promote extremism) or do not leverage the full potential of digital technologies. Extremism experts recognize the need for researchers from other disciplines, like information systems, to contribute their technical expertise for understanding and countering online extremism. This article aims to introduce the field of information systems to the issue of online extremism. Information systems scholars address technology‐related societal issues from a sociotechnical perspective. The sociotechnical perspective describes systems through a series of interactions between social (structure, people) and technical components (physical system, task). We apply the sociotechnical perspective to (1) summarize the current state‐of‐the‐art knowledge of 222 articles in a systematic multi‐disciplinary literature review and (2) propose specific research questions that address two questions (How do digital technologies augment extremism? How can we successfully counter online extremism?).