This monograph introduces a new, systematic taxonomy of Sports Interaction Technology (Sports ITech) that defines a design space of existing and future work in this domain. The authors put the taxonomy in a context of sport science and practice, target outcomes of sports, the underlying factors that influence them, and the role that sports technology plays in supporting sports science and practice. They build on the existing taxonomies and a vast body of literature from multiple domains of HCI, technology, sports science, and related work in Sports ITech, and complement it with identified gaps in the literature. This taxonomy is meant to be used by designers of Sports ITech. It will help better highlight and position existing work as well as provide input and inspiration for the design and deployment of such technology. It offers a description of a design space suitable to support designers, technologists, and sports people with a mindset to design, deploy, and adapt Sports ITech. The authors present this work as a call to action to bring HCI and the sports sciences closer together in the new field of Sports Interaction Technology, and aim to set a shared agenda for future developments. A Design Space of Sports Interaction Technology is a complete guide to navigate the literature from the many underlying disciplines of Sports ITech.