A home for children with special educational needs has been closed after "serious safeguarding concerns" were identified - prompting a police investigation.
Ofsted said it has suspended registration of the children's home at the Kisimul School in Swinderby, and informed police and authorities.
Lincolnshire Police said it is investigating but has made no arrests.
A spokesperson for the school said pupil safety was a priority.
The children's accommodation is on the site of, but is registered separately from, the Kisimul School.
Children with autism, learning disabilities and challenging behaviour are taught at the independent school.
At its last inspection, the school was rated as outstanding by Ofsted and its children's home rated as good.
But a spokesperson for Ofsted said: "We have suspended the registration of the children's home after being made aware of serious safeguarding concerns.
"These have been referred to the police and relevant local authorities.
"It would be inappropriate to comment further while an investigation is under way."
Lincolnshire County Council's, Assistant Director of Children's Services, Heather Sandy, said: "Where we do have children placed at the home, we are working together with parents and carers and making arrangements to find alternative provision.
"This does not affect the Kisimul School," she added.
According to the authority, there were 47 boarders at the school.
A spokesperson for the school said: "We take all allegations very seriously and always ensure they are thoroughly investigated.
"Our staff are fully co-operating with the police as they conduct their investigation."