Ahearn or Ahearne is a surname. It descends from Echthighern mac Cennétig. Notable people with the surname include:
- Blake Ahearn (born 1984), American basketball player
- Bunny Ahearne (1900–1985), British ice hockey promoter
- Joe Ahearne, British television director
- Michael Ahearne (born 1966), academic and author
- Mike Ahearn (1878–1948), American college football coach
- Rick Ahearn (born 1949), American political consultant, longtime Ronald Reagan aide
- T. Franklin Ahearn (1886–1962), Canadian hockey club owner and politician
- Theresa Ahearn (1951–2000), Irish politician
- Thomas Ahearn (1855–1938), Canadian inventor and businessman
- Thomas Ahearn (Australian politician) (born 1929) Australian politician and patent attorney
- William Ahearn (1858–1919), American baseball player