The Old Grammar School is a historic building in Wath, a village near Ripon in North Yorkshire, in England.
The building was constructed in 1684 as a grammar school, with funding from Peter Samwaies, the rector of St Mary's Church, Wath. The building was altered in the mid-18th century, and again in the 19th century. In the 20th century, it was converted into a house. The building was grade II listed in 1951.
The building is constructed of roughcast stone, and has a roof of Westmorland slate with pantiles at the rear, stone coping and shaped kneelers. It has two storeys and is five bays wide. The central doorway has an architrave and a three-light fanlight, and above it is an inscription. The windows are sashes in architraves. At the rear is a two-light mullioned window and an outshut, and in the roof are four pairs of upper crucks.