The Oscar winning actress, who lives in Nairn, described boarding schools as “cruel”, “very lonely” and “isolating”.
Swinton went to the prestigious West Heath Girls School in Kent, where she was classmate of the future Diana, Princess of Wales.
She said: “I think they are a very cruel setting in which to grow up and I don’t feel children benefit from the type of education.
“Children need their parents. That’s why I dislike films like Harry Potter, which tend to romanticise such places.”
Swinton went on to establish her own liberal school, Drumduan Upper School, where her to children were education.
The school has no tests of exams and costs £7,500 per year to attend.
She said: “They learn their science by building a Canadian canoe or making a knife or caramelising onions and they are all happy and inspired.”
The Boarding School Association disagreed with Swinton’s sentiments, saying: “Good, modern British boarding gives students a unique opportunity to forge friendships, create networks across the world and maintain strong family relationships.”