Cashin is a surname of Irish origin. Notable people with the surname include:
- Alice Cashin (1870–1939), Australian nurse
- Bonnie Cashin (c. 1907–2000), American designer
- Eiran Cashin Derby County Football player
- Edward J. Cashin (1927–2007), American historian
- Fergus Cashin (1924–2005), British Journalist
- John L. Cashin Jr. (1928–2011), American dentist, civil rights campaigner, and politician
- His daughter Sheryll, Law professor at Georgetown University Law Center
- John M. Cashin (1892–1970), United States federal judge
- Michael Patrick Cashin (1864–1926), Newfoundland businessman and politician
- Pat Cashin (1968–2016), American clown and actor
- Patrick H. Cashin (1851–1926), American businessman and politician
- Major Peter John Cashin (1890–1977) Canadian businessman, soldier and politician
- Richard Cashin, lawyer, former Canadian politician and trade union leader