The 1956 United States Senate election in Oklahoma took place on November 6, 1956. Incumbent Democratic Senator Mike Monroney ran for re-election to a second term. He avoided a contentious Democratic primary when Lieutenant Governor Cowboy Pink Williams declined to challenge him and easily won renomination. In the general election, he faced Republican state party chairman Douglas McKeever. Even though President Dwight D. Eisenhower was winning the state handily, Monroney won re-election by a wide margin.