Frail older adults are increasingly encouraged to be in control of their health care, in Western societies. However, little is known about how they themselves perceive control in health care. Therefore, this study aims to investigate the concept of health care-related perceived control from the viewpoint of frail older adults. A qualitative interview study was conducted following a Grounded Theory approach. Thirty-two Dutch frail older adults, aged 65 and over, participated in 20 in-depth interviews (n = 20) and three focus group discussions (n = 12). Data were analysed according to techniques of coding and constant comparison. From this analysis constituting factors of perceived control emerged, providing elements of a conceptual model. Perceived control reflects the feeling or belief that health care is under control, which is constituted by five, either internal or external, factors: (I) self-confidence in organising professional and/or informal care, (II) self-confidence in health management in the home setting, (III) perceived support from people in the social network, (IV) perceived support from health care professionals and organisations, and (V) perceived support from (health care) infrastructure and services. Therefore, the concept does not only consist of people's own perceived efforts, but also includes the influence of external sources. Our conceptual model points out what external factors should be taken into consideration by health care professionals and policy makers when enhancing older people's perceived control. Moreover, it can serve as the basis for the development of a measurement instrument, to enable future quantitative research on health care-related perceived control among older adults.