Background <p>Despite the substantial experience and knowledge generated daily by informal caregivers and their well-documented contribution to health outcomes, quality improvement efforts in healthcare continue to focus primarily on patients’ experiences. Yet patients’ perspectives differ in important ways from those of informal caregivers. The aim of the study was to explore how informal caregivers’ experiences are collected and used to inform QI initiatives in healthcare settings, rather than to examine caregivers’ experiences per se.</p> Methods <p>A mixed-methods systematic review with a convergent segregated approach was conducted. Searches in four scientific databases (Medline, Web of Science, PsycInfo, and CINAHL) from inception to 20 May 2025 were conducted. The searches yielded 8,648 records, whereof 83 full texts were screened, and 13 studies met the inclusion criteria.</p> Results <p>Experience-based co-design or its accelerated form were common methods for collecting experiential data. A wide range of interventions were implemented using these data, targeting improvements in clinical care, education, research, or system-level processes. Most studies focused on enhancing clinical care, including changes to care processes, improved interdisciplinary teamwork, and strengthened family-centred communication. System-level interventions addressed areas such as complaints and grievance reporting, and investigation of adverse events.</p> Conclusion <p>Integrating the perspectives of informal caregivers into quality improvement initiatives has the potential to improve clinical care, strengthen medical and nursing education, inform clinical research, and enhance patient safety.</p> Clinical trial number <p>Not applicable.</p> Protocol registration <p>The study protocol was registered on PROSPERO before the commencement of the review (registration number CRD42023400597).</p>