Kelli O'Hara (born April 16, 1975) is an American actress, singer, and songwriter.

O'Hara has been nominated for three Tony Awards, one for her performance as Clara Johnson in The Light in the Piazza, one for her performance as Babe Williams in the Roundabout Theatre Company's revival of The Pajama Game, where she starred alongside Harry Connick, Jr. and Michael McKean, and most recently for her performance as Nellie Forbush in the Lincoln Center Theater revival of South Pacific.

O'Hara was recently seen as Dot/Marie in the L.A. Reprise! concert staging of Sunday in the Park with George. She can be heard as the voice of producer Beth Totenbag on PBS's 2008 animated series Click and Clack's As the Wrench Turns.