Sidney Elmer Simpson (September 20, 1894 - October 26, 1958) was a U.S. Representative from Illinois, husband of Edna Oakes Simpson.
Born in Carrollton, Illinois, Simpson attended the public schools and was graduated from Carrollton High School. During the First World War served in the United States Army, with overseas service. He was owner of Simpson Motor Co. and Simpson Bus Co.. He served as chairman of the Greene County Republican Committee. He served as member of the executive committee of the County Chairman's Association of Illinois. City treasurer of Carrollton, Illinois, for one term. He served as member of Carrollton Board of Education.
Simpson was elected as a Republican to the Seventy-eighth and to the seven succeeding Congresses and served from January 3, 1943, until his death. He served as chairman of the Committee on District of Columbia (Eighty-third Congress). Had been renominated to the Eighty-sixth Congress. He died in Pittsfield, Illinois, October 26, 1958. He was interred in Carrollton City Cemetery, Carrollton, Illinois.