AimThe aim of this qualitative meta‐synthesis was to discover the factors impacting on missed nursing care of nurses through systematic thinking.BackgroundAlthough nurses are responsible for high‐quality care, missed nursing care is common, endangering patient safety. Understanding of the causes related to missed nursing care could help nursing managers improve the quality of nursing care.DesignA qualitative meta‐synthesis guided by the Preferred Reporting Items for Systematic Reviews and Meta‐analyses (PRISMA).MethodsAs a method designed to contribute to knowledge development, meta‐synthesis allows for integration of qualitative study findings using thematic synthesis. Six databases were searched up to October 2021; nine studies met the inclusion and quality assessment criteria and meta‐synthesis were conducted.ResultsThree themes related to the causes why nurses missed nursing care were found. The themes included intrinsic resources (professional and ethical values, ambiguous nurse role, prioritization, education system, and knowledge), system structure (staff and resources shortage, heavy workload but limited time, and organizational management failure), and social environment (communication, working relationship and skill mix, and inappropriate ward layout).ConclusionThe phenomenon of missed nursing care is a global tissue, with variations in its elements but also notable similarities. Meta‐synthesis provides evidence of intrinsic and extrinsic factors that contribute to missed nursing care.Relevance to Clinical PracticeRecognizing and understanding the causes of missed nursing care is essential for nursing managers to ensure patient safety and the provision of high‐quality care.