William Armstrong may refer to:
- Kinmont Willie Armstrong (fl. 16th century), Scottish border reiver, known as "Kinmont Willie"
- William “Willie” Armstrong (1804–?), Newcastle upon Tyne born singer-songwriter
- William Armstrong (Christie's Will) (c. 1602–c. 1658), Scottish border freebooter, known as "Christie's Will"
- William Armstrong (artist) (1822–1914), Canadian artist
- William Armstrong (Virginia) (1782–1865), U.S. Representative from Virginia
- William H. Armstrong (1911–1999), author of the children's book Sounder
- William Hepburn Armstrong (1824–1919), U.S. Representative from Pennsylvania
- William L. Armstrong (born 1937), U.S. Senator from Colorado
- William Armstrong, 1st Baron Armstrong (1810–1900), British industrialist
- William Armstrong, Baron Armstrong of Sanderstead (1915–1980), British civil servant
- William "Duff" Armstrong (1833–1889), 1858 defendant for the murder of James Preston Metzker in Mason County, Illinois
- William T. Armstrong (1929–2005), Canadian Broadcasting Corporation executive
- William W. Armstrong (journalist) (1833–1905), U.S. journalist and politician from Ohio
- William W. Armstrong (politician) (1864–1944), U.S. lawyer and politician in New York state
- William Ward Armstrong, Canadian mathematician and computer scientist
- William Armstrong (footballer) (born 1892), Australian rules footballer
- William Armstrong (music critic) (1858–1942), American music critic
- William Armstrong (American artist) (born 1938), American artist
- William Boardman Armstrong (1883–1954), lawyer and political figure in Nova Scotia, Canada
- William James Armstrong (1826–1915), merchant, miller and politician in British Columbia
- Billy Armstrong (born 1941), politician in Northern Ireland
- Billie Joe Armstrong (born 1972), American rock musician with Green Day
- Bill Armstrong (coach), American college football coach
- Bill Armstrong (ice hockey b. 1966), ice hockey player
- Bill Armstrong (ice hockey b. 1970), ice hockey player and coach
- Bill Armstrong (footballer) (1913–1995), English footballer
- Bill Armstrong (announcer), game show announcer
- Bill Armstrong (politician) (1909–1982), Australian politician
- Bill Armstrong, detective on the Zodiac Killer case
Famous quotes containing the words william and/or armstrong:
“No bubble is so iridescent or floats longer than that blown by the successful teacher.”
—Sir William Osler (1849–1919)
“I am black: I am the incarnation of a complete fusion with the world, an intuitive understanding of the earth, an abandonment of my ego in the heart of the cosmos, and no white man, no matter how intelligent he may be, can ever understand Louis Armstrong and the music of the Congo.”
—Frantz Fanon (1925–1961)