The 2020 Wisconsin Republican presidential primary took place on April 7, 2020. It is one of the Republican Party primaries for the 2020 presidential election.

Although American Samoa did not participate in the 2020 presidential election because it is a U.S. territory and not a state, it still participated in the U.S. presidential primaries and caucuses. Former mayor Michael Bloomberg won the Democratic caucus, held on March 3. The Republican caucus, in the form of a territorial convention held on March 18, endorsed incumbent President Donald Trump.