William Vincent Shannon (August 24, 1927 – September 27, 1988) was an American journalist, author, and United States Ambassador to Ireland from 1977 to 1981 under President Jimmy Carter.

[3] He also authored the books The American Irish: A Political and Social Portrait (1964), The Heir Apparent (1967), and They Could Not Trust the King (1974).

In 1975 he received the Gold Medal of the Éire Society of Boston for service to literature.

He was an associate fellow of Yale University's Morse College from 1966, and in 1961–62 was fellow-in-residence at the Center for the Study of Democratic Institutions in Santa Barbara, California.

After confirmation by the Senate, he presented his credentials to Irish leaders on July 20, 1977, and had the official title of Ambassador Extraordinary and Plenipotentiary.