The 1948 United States Senate election in Oklahoma took place on November 2, 1948. Incumbent Republican Senator Edward H. Moore declined to run for re-election. A crowded Democratic primary, including the former Governor, multiple members of Congress, and several statewide elected officials, developed; former Governor Robert S. Kerr won a slim plurality in the initial primary and then defeated former Congressman Gomer Smith by a wide margin in the runoff. On the Republican side, Congressman Ross Rizley had an easy path to the nomination. Kerr defeated Rizley in a landslide, largely similar to President Harry S. Truman's landslide victory in Oklahoma over Republican presidential nominee Thomas E. Dewey.