The Rural Municipality of Rosthern No. 403 (2016 population: ) is a rural municipality (RM) in the Canadian province of Saskatchewan within Census Division No. 15 and Division No. 5. It is located in the central portion of the province north of the City of Saskatoon.
The RM of Rosthern No. 403 incorporated as a rural municipality on December 9, 1912.
In the 2021 Census of Population conducted by Statistics Canada, the RM of Rosthern No. 403 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.
In the 2016 Census of Population, the RM of Rosthern No. 403 recorded a population of living in of its total private dwellings, a change from its 2011 population of . With a land area of , it had a population density of in 2016.
The following urban municipalities are surrounded by the RM.
The following unincorporated communities are within the RM.
The RM of Rosthern No. 403 is governed by an elected municipal council and an appointed administrator that meets on the second Tuesday of every month. The reeve of the RM is Roger Kinzel while its administrator is Amanda McCormick. The RM's office is located at 1001 6th Street, Rosthern, SK.