| Mark Senn | |
| Birthname: | Mark Cecil Senn |
| Birth Date: | 1878 6, df=yes |
| Birth Place: | Oneida, Ontario, Canada |
| Spouse: | Etta May Moore m. 1899[1] |
| Riding: | Haldimand |
| Predecessor: | Francis Ramsey Lalor |
| Successor: | Earl Catherwood |
| Term Start: | December 1921 |
| Term End: | April 1949 |
| Profession: | farmer, merchant, teacher |
| Party: | Conservative (1867–1942) Progressive Conservative |
Mark Cecil Senn (1 June 1878 – 10 January 1951) was a Canadian farmer, merchant, teacher and politician. Senn served as a Conservative and Progressive Conservative party member of the House of Commons of Canada. He was born in Oneida, Ontario.
He was first elected to Parliament at the Haldimand riding in the 1921 general election, initially under the Conservative party. Senn was re-elected in 1925, 1926, 1930, 1935, 1940 and 1945. He did not stand for re-election in 1949 due to health problems. Senn died at his residence in Oneida Township on 10 January 1951, survived by his wife, three sons and three daughters.[2]