In 1996, Tiernan won the Channel 4 "So You Think You're Funny" award. Two years later he was awarded the Perrier Comedy Award at the 1998 Edinburgh Festival Fringe and won the Best Stand-Up Award at the British Comedy Awards. In 2003, he won the Nokia Best of the Fest Award and the Orange People Choice Award at the Edinburgh Comedy Festival. In 2006, he won Ireland's Funniest Living Person Award at the People of the Year Awards.