Jan Decleir (born 14 February 1946) is a Belgian movie and stage actor. He was born in Niel, Antwerp.

His first big role was in Fons Rademakers' Mira (1971). He starred in Academy Award winning movies Karakter and Antonia and the Oscar-nominated social drama Daens.

For his role in The Barons, he received the Magritte Award for Best Supporting Actor.