Moses Edwin Clapp (May 21, 1851 – March 6, 1929) was an American lawyer and politician.

Born in Delphi, Indiana, Clapp moved with his parents to Hudson, Wisconsin.

In 1900, he entered the special election for Minnesota's seat in the United States Senate that was made vacant by the death of Cushman Davis.

Clapp, along with Hiram F. Stevens, Ambrose Tighe, Thomas D. O'Brien, and Clarence Halbert, was also a co-founder of William Mitchell College of Law.

In 1906, he presented A Brief History of the Delaware Indians by Richard C. Adams for publication to the 59th Congress.