Raymond Martin Marie Ghislain, Baron Lemaire (Ukkel, 28 May 1921 - Sint-Lambrechts-Woluwe, 13 August 1997) was an art historian and an architectural historian, a leading expert in conservation and professor at the Catholic University of Leuven and later at the KU Leuven and the Université catholique de Louvain in Louvain-la-Neuve.