The Muhlenberg legend is an urban legend in the United States and Germany. According to the legend, the single vote of Frederick Muhlenberg, the first ever Speaker of the US House of Representatives, prevented German from becoming an official language of the United States. The story has a long history and has been told in several variations, which may be based in part on actual events.

Frederick Augustus Conrad Muhlenberg was an American minister and politician who was the first Speaker of the United States House of Representatives and the first Dean of the United States House of Representatives. A member of the Federalist Party, he was delegate to the Pennsylvania state constitutional convention and a member of the U.S. House of Representatives from Pennsylvania and a Lutheran pastor by profession, Muhlenberg was born in Trappe, Pennsylvania. His home, known as The Speaker's House, is now a museum and is currently undergoing restoration to restore its appearance during Muhlenberg's occupancy.