A care charity that provides services for about 90 adults in Oxfordshire says it will shut them by the end of May.
Hft, which runs several services in Milton, near Didcot, said running them was leaving it with a £5,000 shortfall every week.
Its chief executive said that was the result of "chronic underfunding of adult social care".
Relatives of people who use the services said their imminent closure left them feeling "absolutely shocked".
Steve White, Hft's chief executive, said underfunding in social care nationally was a "disgrace".
He said: "These are very vulnerable people and they deserve great care, great accommodation and great support and that requires adequate funding."
Mr White added: "The shortfall between the cost of running the services each week is nearly £5,000 on the ground.
"That is just unacceptable and charities just cannot bear those costs."
Graham Williams' daughter Lydia, 39, has lived at a Hft-run house in Milton since 2003. She has epilepsy, multiple learning difficulties and hemiplegia.
Mr Williams said: "Clearly it's going to cause tremendous anxiety and stress for residents to move."
The charity's residential services will close on 13 April and its day services, which are used by about 60 people, will close on 31 May.
An Oxfordshire County Council spokeswoman said: "Hft's business decision to close the Milton Heights site is supported by the council and we will continue to work with it and other providers when operating difficulties are experienced."
The Department of Health and Social Care said it was providing councils with an extra £1.5bn for adult and children's social care this year to "help meet rising demand and stabilise the social care system".