Given ICH-GCP’s role in shaping IRB standards in most jurisdictions, clarifying the function and definition of nonscientific members is crucial. ICH-GCP 3.2.1 requires a nonscientific member but its definition focuses on who they are not rather than who they are, creating ambiguity and varied interpretations. This paper reviews the idea of nonscientific members of the IRB to understand their definitions and roles based on current literature. This is because, despite the ICH-GCP’s mandate, recent research is scarce. Our review identifies that (...) in the current literature, various definitions and roles are ascribed to nonscientific members, resulting in a lack of clarity. Following our thematic analysis, we highlight two main interpretations of the nonscientific member’s definition: one as a distinct perspective from scientific members and another as an embodiment of “ordinariness” to minimize bias. In addition, we also highlight three primary roles: reviewing consent forms, representing public and participant interests, and providing oversight. Some findings may not align with current IRB practices, and without clear definitions, adherence to ICH-GCP guidelines may be inconsistent. (shrink)