The study of interruptions and multitasking as central elements of clinical workflow has increasingly featured as a topic of investigation within the healthcare sector due to their perceived implications for the efficient and safe delivery of care. The body of research in this area is large and growing, covering a wide range of settings and healthcare professionals. Drawing on findings from the fields of experimental psychology and aviation, the assumption that interruptions and multitasking may negatively impact clinical work has dominated research of these phenomena in healthcare. Evidence of the effects of interruptions and multitasking is neither consistent nor conclusive, however, due in part to the complexity of workflow in healthcare and the corresponding challenges to studying it (Walter, Acad Emerg Med 25:1178–1180, 2018; Walter et al., Int J Hum Comput Stud 79:118–125, 2015). A predominance of descriptive studies (Kannampallil et al., 2016) has quantified aspects of clinical work in a range of settings, including quantifying the pervasiveness of interruptions and multitasking. However, these studies were generally not designed to assess the impacts of these phenomena. A smaller group of studies has assessed various effects of multitasking and, more commonly, interruptions. These studies have reported a rather heterogeneous range of results. This chapter provides an overview of the current evidence about the role of interruptions and multitasking in healthcare and their impact on workflow and outcomes.