Michael E. Guest was the U.S. Ambassador to Romania, appointed by President George W. Bush. Guest was sworn in on September 18, 2001 and took up his duties on September 24, 2001.

A foreign service officer since 1981, Guest is the first openly gay man to be confirmed by the U.S. Senate to serve in such capacity. (The first openly gay ambassador, James Hormel, received a recess appointment from Bill Clinton after the Senate failed to confirm his nomination.)[1] He resided together with his domestic partner at the American Embassy in Bucharest until 2004 when his appointment by President Bush ended.