Santa Maria in Calanca is a municipality in the Moesa Region in the Swiss canton of the Grisons .

Santa Maria in Calanca is first mentioned in 1219 as sancte Marie in Calanca.

Santa Maria in Calanca has an area, as of 2006, of 9.3 km2 (3.6 sq mi). Of this area, 5.6% is used for agricultural purposes, while 73.2% is forested. Of the rest of the land, 1.6% is settled (buildings or roads) and the remainder (19.6%) is non-productive (rivers, glaciers or mountains).

Before 2017, the municipality was located in the Calanca sub-district of the Moesa district, after 2017 it was part of the Moesa Region.