Moses Edwin Clapp (May 21, 1851 – March 6, 1929) was an American politician. He served in the United States Senate as a Republican from Minnesota. He was elected to the Senate in 1901 to fill the vacancy caused by the death of Cushman Davis, temporarily filled by Charles A. Towne. He was reelected in 1904 and 1910, serving from January 23, 1901 to March 3, 1917. He was not renominated by the party in 1916.