St. Mary's, officially named the Municipality of the District of St. Mary's, is a district municipality in Guysborough County, Nova Scotia, Canada. Statistics Canada classifies the district municipality as a municipal district.
The district municipality occupies the western half of the county and its administrative seat is in the village of Sherbrooke.

Demographics
In the 2021 Census of Population conducted by Statistics Canada, the Municipality of the District of St. Mary's had a population of living in of its total private dwellings, a change of from its 2016 population of . With a land area of , it had a population density of in 2021.

Electoral districts
The district municipality is divided into seven electoral districts for municipal representation:






