the development codename for the Microsoft Windows XP computer operating system.

James McNeill Whistler (1834–1903), an American-born British painter

Whistler-Blackcomb, the ski resort that will host the 2010 Winter Olympics Alpine events

Whistler (TV series), a mystery/drama/thriller premiering in 2006 on CTV and The-N.

Someone who whistles.

Whistler, British Columbia, the municipality of the 2010 Winter Olympics Alpine events

Rex Whistler (1905–1944), a British painter

James Whistler, mysterious inmate in the television series Prison Break's third season

Charles Whistler (1856–1913), a British writer

Abraham Whistler, mentor to the Marvel Comics character Blade in film and animated continuity

The Whistler, a classic mystery drama radio show.

Laurence Whistler (1912– 2000), a British glass engraver and poet

The Hoary Marmot.

George Washington Whistler (1800–1849), an American railroad engineer

Whistler Mountain, the geographic entity that is the mountain where the above ski resort/village is based

Whistler (radio), a very low frequency radio phenomenon.

Whistler (band), a UK indie band

a Whistler (bird), a genus of Australian passerine birds in the family Pachycephalidae.

Anna McNeill Whistler (1804–1881), mother of the artist James McNeill Whistler and model for the painting Whistler's Mother. Wife of George Washington Whistler.