Markdale is a community in the Municipality of Grey Highlands, in Grey County, Ontario, Canada. The population was 1,216 in 2016, an increase of 3.5% from 1,175 in 2011. In 2016, the average age of the population was approximately 43 years old.

Grey Highlands is a municipality in the southeast corner of Grey County, Ontario, Canada. It was formed on January 1, 2001, by the amalgamation of the village of Markdale and the townships of Artemesia, Euphrasia and Osprey, which included the unincorporated hamlets of Eugenia, Ceylon, Maxwell, Singhampton, Priceville, Kimberley, Badjeros, and Feversham. The former village of Flesherton is also located within the municipality and was amalgamated with Artemesia Township in 1998.