The purpose of this study was to delimit group psychological abuse through a psychosocial approach. An operational definition of the phenomenon and a taxonomy of group psychological abuse strategies were proposed based on a review of the scientific literature. A panel of 31 experts in the area evaluated the content of the taxonomy and judged the severity of the strategies through a Delphi study. Group psychological abuse was defined by the application of abusive strategies, their continued duration, and their ultimate aim, i.e., subjugation of the individual. The taxonomy showed adequate content validity. Expert's judgments allowed for hierarchically organizing the strategies based on their severity, being the most severe those directed to emotional area. Operationalizing, classifying and organizing the strategies hierarchically contributes to a better delimitation of the phenomenon, which is useful for both the academic and applied fields