The Rural Municipality of Lakeside No. 338 (2016 population: ) is a rural municipality (RM) in the Canadian province of Saskatchewan within Census Division No. 10 and Division No. 4. It is located in the east-central portion of the province.
The RM of Lakeside No. 338 incorporated as a rural municipality on December 12, 1910.
The following urban municipalities are surrounded by the RM.
The following unincorporated communities are within the RM.
In the 2021 Census of Population conducted by Statistics Canada, the RM of Lakeside No. 338 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 Lakeside No. 338 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.
Its economy is predominantly agricultural.
The RM of Lakeside No. 338 is governed by an elected municipal council and an appointed administrator that meets on the second Thursday of every month. The reeve of the RM is Arnold Boyko while its administrator is Julie Knafelc. The RM's office is located in Quill Lake.