Michael San Nicolas Democratic Michael San Nicolas Democratic The 2020 United States House of Representatives election in Guam was held on Tuesday, November 3, 2020, to elect the non-voting Delegate to the United States House of Representatives from Guam's at-large congressional district.

Incumbent freshman Delegate Rep. Michael San Nicolas, who was first elected in 2018, is seeking a second term.

He was challenged by former U.S. Rep. Robert A. Underwood (Guam delegate from 1993 to 2003), a Democrat, and Republican Wil Castro.

As no one got a majority of the vote, San Nicolas and Underwood faced off in a runoff within two weeks.

All three certified candidates advanced to the U.S. House general election and appeared on the ballot in November 2020.