gesso

thumb|A restored gesso panel representing Martin of Tours|St. Martin of Tours, from St. Michael and All Angels Church, Lyndhurst, Hampshire

Gesso (; 'chalk', from the , from ), also known as "glue gesso" or "Italian gesso", is a white paint mixture used to coat rigid surfaces such as wooden painting panels or masonite as a permanent absorbent primer substrate for painting. It consists of a binder mixed with chalk, gypsum, pigment, or any combination of these.