Tiernan

Tiernan (MacTiarnaigh or Ó Tiarnáin; also spelled Tirnan, Tierney) is an Irish surname. Tiernan is also an anglicisation of Tiarnán, a given name derived from the Irish word tiarna "lord" + -án (diminutive suffix).

As surname
Notable people with the surname Tiernan include:
 * Andrew Tiernan (born 1965), English actor
 * Dan Tiernan (born 1996), English stand-up comedian
 * Bob Tiernan, American politician
 * Cate Tiernan (born 1961), pen name of Gabrielle Charbonnet, American author
 * Fergus Tiernan (born 1982), Scottish football midfielder
 * Frances Christine Fisher Tiernan (1846–1920), pen name "Christian Reid", American novelist, author
 * Greg Tiernan (born 1965), Irish-born-Canadian-based animator, director, voice actor
 * Jonathan Tiernan-Locke (born 1984), British cyclist
 * Mary Spear Nicholas Tiernan (1835–1891), American writer
 * Mike Tiernan (1867–1918), American professional baseball player
 * Robert Tiernan (1929–2014), American lawyer, politician
 * Sonja Tiernan, Irish historian
 * Tommy Tiernan (born 1969), Irish comedian, actor, writer, presenter

As forename
Notable people with the forename Tiernan include:
 * Tiernan Brady, Irish-Australian LGBT rights campaigner
 * Tiernan Killeen (born 2003), Irish hurler
 * Tiernan McCann (born 1991), Irish Gaelic footballer
 * Tiernan O'Halloran (born 1991), Irish rugby player