In 3 studies, we developed and tested the first comprehensive, self-report measure of workplace interruptions. The Workplace Interruptions Measure (WIM) is based on a typology of interruptions that included intrusions, distractions, discrepancy detections, and breaks. The four-factor structure was reduced to a 12-item measure in Study 1 (N = 317) and confirmed in a diverse sample of employees in Study 2 (N = 160). Study 3 (N = 323) further examined the psychometric properties of the WIM in a sample of university faculty and staff. Studies 2 and 3 demonstrated that both effort-enhancing interruptions (intrusions, distractions, and discrepancy detections) and recovery-enhancing interruptions (breaks) were associated with stressors and strains. Distractions, discrepancy detections, and breaks uniquely predicted strain outcomes beyond other workplace stressors (i.e., quantitative workload, interpersonal conflict, and role conflict). We discuss implications of the WIM for the theory and practice of interruptions research.