Haylie Duff (born February 19, 1985) is an American actress and pop music singer.
Duff was born in Houston, Texas. Her mother is the producer Susan Duff. Her father, Bob Duff, is a convenience store owner. She is commonly known as the older sister of Hilary Duff.
Duff has appeared in several episodes of Lizzie McGuire, which stars her sister Hilary. She has also appeared on another Disney Channel show, That's So Raven, and on other TV programs including Joan of Arcadia, American Dreams, Boston Public, and Chicago Hope. She played Summer, a stereotypical popular teenager, in the 2004 independent film, Napoleon Dynamite. In 2005, Duff joined the cast of 7th Heaven, playing Sandy Jameson, best friend to Simon's girlfriend.