A member of staff at Priory Ruskin Academy in Grantham has been suspended.
They were arrested in connection with what the school describes as “an alleged child protection issue”.
In a letter sent out to parents on Wednesday, Priory headteacher Clive Shepherd said: “Last Friday (May 3), the Academy was made aware of an alleged child protection issue which was said to involve a member of staff.
“In line with our safeguarding policy, this person will not be in school while inquiries into the allegation are carried out.
“The inquiries are being undertaken by Lincolnshire Police and Lincolnshire Social Services after the allegation was brought to their attention by the Academy. It would therefore be inappropriate to make any further comment while those inquiries are taking place.
“Our primary concern, as ever, is the welfare and care of children at the school. We have been reminded that rumours and speculation at this time can only upset the wellbeing of our children and potentially compromise any police invetigations.”
A police statement said: “On Friday, May 3, police arrested a 32-year-old local woman in relation to a child safeguarding issue. The suspect has been released on police bail pending further inquiries.”