Mullin is a surname of Irish origin. Notable people with the name include:

• John Mullin (journalist) (born 1964), British newspaper editor
• Mike Mullin (author), young adult fiction writer
• Willard Mullin (1902–1978), American sports cartoonist

• George Mullin (VC) (1892–1963), American recipient of the Victoria Cross during World War I
• Hugh P. Mullin (1878–1948), Philippine–American War Medal of Honor recipient

• Chris Mullin (politician) (born 1947), British Labour Party Member of Parliament
• Gene Mullin (1927–2021), American politician
• Gerald T. Mullin (1900–1982), American businessman, lawyer, and politician
• Joseph Mullin (1811–1882), New York lawyer and politician
• Markwayne Mullin (born 1977), U.S. Senator for Oklahoma
• Michael P. Mullin (born 1981), Virginia politician
• Washington Beltrán Mullin (1914–2003), Uruguayan lawyer and politician, president of the National Council of Government 1965-1966

• Jack Mullin (1913–1999), American pioneer of magnetic tape sound recording
• John W. Mullin (1925–2009), British chemical engineer, known for crystallisation

• Brendan Mullin (born 1963), Irish rugby union player
• Chris Mullin (basketball) (born 1963), American basketball player
• Emma Mullin (born 1985), Irish ladies' Gaelic footballer and association footballer
• George Mullin (baseball) (1880–1944), baseball pitcher
• John Mullin (footballer) (born 1975), English association footballer, mostly played for Burnley, Rotherham and Tranmere Rovers
• Mike Mullin (bowler), American ten-pin bowler
• Oisín Mullin (born 2000), Irish Gaelic footballer and Australian rules footballer
• Paul Mullin (footballer, born 1974), English footballer, mostly played for Accrington Stanley and Morecambe
• Paul Mullin (born 1994), English footballer, has mostly played for Morecambe and Wrexham

• Glenn Mullin (born 1949), Tibetologist and author
• Herbert Mullin (1947–2022), American serial killer
• Jack Mullin (1913–1999), American engineer
• Mabel D. Mullin (1882–?), social club president in Washington D.C.

• Mullen, a surname
• Mullins (surname)
• Mullen (disambiguation)
• Mullens (disambiguation)
• Mullins (disambiguation)