Oscar R. Knutson (October 9, 1899 – June 15, 1981) was an American lawyer and judge from Minnesota.
The son of immigrant parents, he did not learn to speak English until he entered school.
Knutson practiced law in Warren with Julius J. Olson, who also became a Minnesota Supreme Court justice.
On May 7, 1948, he was appointed to the Minnesota Supreme Court by Governor Luther Youngdahl, succeeding Olson.
On January 25, 1962, he was appointed Chief Justice by Governor Elmer L. Andersen and was elected in 1964 and re-elected in 1970.