The United States ambassador to Guinea-Bissau is the official representative of the president of the United States to the head of state of Guinea-Bissau. The U.S. ambassador to Senegal is concurrently commissioned to Senegal and Guinea-Bissau.

Until 1974, Guinea-Bissau had been a colony of the Portuguese Empire as Portuguese Guinea. After a period of revolutionary warfare, Guinea-Bissau unilaterally declared its independence on September 24, 1973. Following the April 1974 Carnation Revolution in Portugal, it granted independence to Guinea-Bissau on September 10, 1974. The United States recognized the Republic of Guinea-Bissau on the same day. The U.S. Embassy Bissau was established on June 30, 1976, with Dean Curran as Chargé d'Affaires ad interim.^[1]

The first three ambassadors to Guinea-Bissau were concurrently commissioned to Cape Verde while resident in Bissau. From 1983 until 1998, U.S. ambassadors were solely commissioned to Guinea-Bissau.^[2] In 1998 the U.S. embassy in Bissau was closed,^[3] and there has been no U.S. embassy in Bissau since then. Since 2002, the U.S. ambassador to Senegal has also been commissioned as the ambassador to Guinea-Bissau, while resident in Dakar.