Weir is a surname. It may refer to:

People

• Alison Weir (born 1951), British writer and historian
• Alison Weir (activist), American activist and writer
• Amanda Weir (born 1986), American Olympic swimmer
• Andrew Weir, 1st Baron Inverforth (1865–1955), British businessman and minister
• Andy Weir (born 1972), American science fiction writer
• Andy Weir (footballer) (1937–1992), Scottish footballer
• Arabella Weir (born 1957), British actress
• Barbara Weir (c. 1945–2023), Indigenous Australian artist and politician
• Benjamin Weir (1923–2016), American missionary held hostage in Lebanon in 1985
• Bill Weir (born 1967), American television journalist
• Bob Weir (born 1947), American guitar player, a founding member of the Grateful Dead
• Bruce Weir (born 1943), New Zealand geneticist
• Caroline Weir (born 1995), Scottish footballer
• David Weir (footballer) (1863–1933), English footballer
• David Weir (journalist)
• David Weir (athlete) (born 1979), British Paralympic wheelchair athlete
• David Weir (Scottish footballer) (born 1970)
• Doddie Weir (1970–2022), Scottish rugby player
• Elizabeth Weir (born 1948), Canadian politician and lawyer
• Erin Weir (born 1982), Canadian politician
• Fred Weir, Canadian journalist
• Frank Weir (cricketer) (1903–1969), New Zealand cricketer
• Gillian Weir (born 1941), New Zealand organist
• Graham Weir (born 1984), Scottish footballer
• Harrison Weir (1824–1906), English writer and artist
• J. Alden Weir (1852–1919), American painter
• James Weir (disambiguation), various people named James, Jim or Jimmy Weir
• Jeremy Weir (born 1964), Australian geologist, banker and businessman, CEO of Trafigura
• John Ferguson Weir (1841–1926), American painter and sculptor
• Johnny Weir (born 1984), American figure skater
• Judith Weir (born 1954), British composer
• Leonard Weir (born 1928), Australian actor
• Lindsay Weir (cricketer) (1908–2003), New Zealand Test cricketer
• Michael or Mike Weir (disambiguation), various people
• Molly Weir (1910–2004), British actress
• Norman Weir (1893–1961), New Zealand major general
• Peter Weir (born 1944), Australian film director
• Peter Weir, Baron Weir of Ballyholme (born 1968), Northern Ireland politician
• Peter Weir (footballer) (born 1958), Scottish footballer
• Phil Weir (1901–1963), Scottish footballer
• Robert Weir (disambiguation), various people
• Robbie Weir (born 1988), Northern Irish footballer
• Stephnie Weir (born 1967), American actress, comedian and writer
• Steve Weir, American politician
• Thomas Weir (1599–1670), Scottish Covenanter and presumed occultist
• Thomas Weir (American soldier) (1838–1876), American cavalry captain who attempted to come to the aid of George Armstrong Custer at Custer's Last Stand
• Tom Weir (1914–2006), Scottish mountain climber, author and broadcaster
• Walter Weir (1929–1985), Canadian politician

Fictional characters

• Brett Weir, in The Jerky Boys: The Movie
• Elizabeth Weir (Stargate), in the television series Stargate Atlantis and Stargate SG-1
• Lindsay Weir (Freaks and Geeks), in the television series Freaks and Geeks