Francis Ryan Duffy (June 23, 1888 – August 16, 1979) was an American lawyer, politician, and jurist from Wisconsin.

He served in the United States Army during World War I from 1917 to 1919, attaining the rank of Major.

[1][2][3] Duffy was elected as a Democrat to the United States Senate and served from March 4, 1933, to January 3, 1939.

[2] Duffy was nominated by President Franklin D. Roosevelt on June 21, 1939, to a seat on the United States District Court for the Eastern District of Wisconsin vacated by Judge Ferdinand August Geiger.

[4] He served as Chief Judge and as a member of the Judicial Conference of the United States from 1954 to 1959.