| Oscar R. Olson | |
| State: | Wisconsin |
| State Senate: | Wisconsin |
| Term Start: | January 6, 1919 |
| Term End: | January 1, 1923 |
| Predecessor: | Platt Whitman |
| Successor: | Olaf H. Johnson |
| Office1: | Register of Deeds of Green County, Wisconsin |
| Term Start1: | January 1, 1893 |
| Term End1: | January 1, 1899 |
| Predecessor1: | J. A. Kettleson |
| Successor1: | John Lewis |
| Birth Date: | 24 March 1869 |
| Birth Place: | Jordan, Wisconsin, U.S. |
| Restingplace: | Old York Lutheran Cemetery, York, Green County, Wisconsin |
| Allegiance: | United States |
| Branch: | Wisconsin National Guard United States Volunteers |
| Rank: | Captain |
| Serviceyears: | 1895 - 1901 |
| Unit: | 1st Reg. Wis. Infantry |
| Battles: | Spanish–American War |
Oscar R. Olson (March 24, 1869November 23, 1945) was an American farmer, banker, and Republican politician from Blanchardville, Wisconsin. He was a member of the Wisconsin Senate, representing Wisconsin's 17th Senate district during the 1919 and 1921 sessions. He also served three terms as register of deeds of Green County, Wisconsin.
Olson was born in Jordan, Wisconsin. he was the son of Rollin Olson (1832–1898) and Mary (Peterson) Olson (1837–1913),[1] who immigrated from Norway in 1845.[2] He attended Valparaiso University.[2] During the Spanish–American War, Olson served in the Wisconsin National Guard, achieving the rank of captain.[2] He died on November 23, 1945[2] and was buried in Old York Lutheran Cemetery in Green County, Wisconsin.[3]
Olson was elected to the Senate in 1918.[2] Previously, he served three terms as register of deeds of Green County, Wisconsin.[2] He was a Republican.[2]