Background: Health care provided to older adults must take into account the characteristics of chronic diseases and the comorbidities resulting from ageing. However, health services are still too oriented towards acute situations. To overcome this problem, the World Health Organization (WHO) proposed a set of Age-Friendly Principles that seek to optimize the provision of health care for this population. This article aims to understand how such Principles are considered in the implementation of age-friendly health care worldwide. Methods: A systematic review was conducted to synthesize the literature on age-friendly health care in accordance with the PRISMA recommendations in the PubMed, Web of Science, and Scopus databases. Results: The research identified 34 articles, with only seven recognizing the WHO Principles and only four using the implementation toolkit. In addition, in the context of primary care, three studies recognize the WHO Principles, but only two use the toolkit. Conclusions: The WHO Principles are being implemented in health care, but in a smaller scale than desired, which reveals possible flaws in their dissemination and standardization. Thus, a greater scientific investment in age-friendly health care should be considered, which represents a greater operationalization of the Principles and an evaluation of their effectiveness and impacts.