Brash is a surname. Notable people with the surname include:
Alan Brash (1913–2002), Presbyterian minister in New Zealand Alan Brash (pharmacologist) (born 1949), Scottish pharmacologist Don Brash (born 1940), New Zealand politician James Brash (1881–1961), Australian organist, adjudicator and composer Jonathan Brash, British politician Marion Brash (1931–2022), American actress Matt Brash (veterinarian), British veterinarian and television presenter Matt Brash (baseball), (born 1998), Canadian baseball player Peter Brash (born 1954), American television soap opera writer Thomas Brash (1874–1957), New Zealand dairy executive and Presbyterian William W. Brash III, American judge