Haas can refer to:
- Haas School of Business at the University of California, Berkeley
- Haas Automation, a machine tool company
- Haas effect, a psychoacoustic effect
- Haas Pavilion at the University of California, Berkeley
- Newman/Haas Racing, an auto racing team
- Haas (rocket), a Romanian launch system
- Seri dialect name for the Honey Mesquite tree
- Hardware as a Service, a variation of Infrastructure as a service
Haas as a surname may refer to:
- Andreas Haas (born 1982), German footballer
- Arthur Erich Haas (1884–1941), Austrian physicist
- Bernt Haas (born 1978), Austrian football (soccer) player
- Bill Haas (born 1982), American professional golfer
- Bob Haas (born 1942), former chairman of Levi Strauss & Co.
- Carl Haas (born 1930), American auto racing impresario
- Charles F. Haas (born 1913), American film and television director
- Charles S. Haas (born 1952), American screenwriter and actor
- Charlie Haas (born 1972), American professional wrestler
- Christl Haas (1943–2001), Austrian Olympic skiing champion
- Clark Haas (fl. 1957-1973), American cartoonist
- Conrad Haas (1509–1576), Austrian military engineer
- Daniel Haas (born 1983), German footballer
- Darius de Haas (born 1968), American stage actor and singer
- David Haas (born 1957), American author and composer of liturgical music
- Dolly Haas (1910–1994), German-American actress
- Earle Haas (1888–1981), inventor of the modern menstrual tampon
- Eddie Haas (born 1935), American baseball outfielder and manager
- Eduard Haas (1897–19??), Austrian inventor of Pez candy
- Ernst Haas (1921–1986), Austrian photographer and photojournalist
- Ernst B. Haas (1924–2003), American political scientist
- Frank Joseph Haas, former Grand Master of the Grand Lodge of West Virginia
- Fred Haas (ca. 1915–2004), American golfer
- Fritz Haas (zoologist) (1886–1969)
- Geertruida de Haas-Lorentz (1885–1973), Dutch physicist
- Gene Haas (born 1952), American machine tool manufacturer
- Georg Haas (physician) (1886–1971), German medical doctor
- Georg Friedrich Haas (born 1953), Austrian composer
- Hans Haas (1886–1935), German Protestant theologian
- Harald Haas (born 1990), Austrian software developer and politician
- Helmut Haas (fl. 1949), discoverer of the Haas effect, a psychoacoustic effect
- Hugo Haas (1901–1968), Czech film actor and director
- Jacob de Haas (1872–1937), UK journalist and an early leader of the Zionist movement
- Jay Haas (born 1953), American professional golfer
- Josef Haas (born 1937), Swiss cross country skier
- Joseph Haas (1879–1960), German composer
- Karen L. Haas, American government administrator and lobbyist
- Karl Haas (1913–2005), American classical music radio show host
- Lukas Haas (born 1976), American film actor
- Mario Haas (born 1974), Austrian football (soccer) forward
- Mary Haas (1910–1996), American linguist
- Mauritz de Haas (1832–1895), Dutch-American marine painter
- Maximilian Haas (born 1985), German footballer
- Monique Haas (1909–1987), French pianist
- Moose Haas (born 1956), American baseball player
- Mule Haas (1903–1974), American baseball player
- Nico de Haas (1907–ca. 2000), Dutch National-Socialist editor, photographer, and artist
- Pavel Haas (1899–1944), Czech Jewish composer
- Richard Haas (born 1936), American muralist
- Robert Haas (clergyman), 19th-century German Lutheran minister
- Robert Haas (musicologist) (1886–1960), Austrian musicologist
- Russ Haas (1974–2001), American professional wrestler
- Saskia Rao-de Haas, Dutch cellist of music from India
- Sidney V. Haas, M.D. (1870–1964), American pediatrician and originator of the Specific Carbohydrate Diet
- Thomas J. Haas, American university president
- Tommy Haas (born 1978), German tennis player
- Toxey Haas (born 1960), American businessman
- Wander Johannes de Haas (1878–1960), Dutch physicist and mathematician
- Walter A. Haas (1889–1979), American president and chairman of Levi Strauss & Co.
- Walter A. Haas, Jr. (1916–1995), American president and chairman of Levi Strauss & Co.
- Walter H. Haas, (born 1917), American amateur astronomer, founder of the Association of Lunar and Planetary Observers (ALPO)
- Waltraut Haas (born 1927), Austrian actress and singer
- Wolf Haas (born 1960), Austrian author
- Wolfgang Haas (born 1948), archbishop in Liechtenstein