Haylie Katherine Duff (born February 19 1985) is an American actress and singer best known for her supporting role on 7th Heaven as well as starring in the films Material Girls and Napoleon Dynamite.

Duff was born in Houston, Texas. Her mother, Susan Duff, is a producer. Robert Erhard Duff, Haylie's father, resides at the family home in Houston to maintain the family's convenience store business. Haylie is two and a half years older than her sister, Hilary Duff, who is relatively more well known than Haylie for her own music career and as an actress.

She appeared in several episodes of Lizzie McGuire; 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 the TV show 7th Heaven, playing Sandy Jameson, best friend to Simon's girlfriend.

Duff was also in a straight to DVD release, Cindy and The Halo Boy, co-starring Frankie Muniz of Malcolm in the Middle fame. In the film, Duff played the leader of a clique of girls in high school who was pregnant with a baby fathered by Muniz's character, nicknamed "Geekling", the leader of a clique of nerdy boys who had wispy mustaches and played the video game Halo. In summer 2006, Duff joined the Broadway cast of Hairspray, portraying mean girl Amber Von Tussle, and playing the part through the beginning of October 2006. Duff has also starred in Material Girls.

Duff is also scheduled to shoot a horror film with Crispin Glover, The I Scream Man.

Duff wrote or co-wrote several songs on three of Hilary Duff's albums, Metamorphosis (2003), Hilary Duff (2004), and the song "Gypsy Woman", on Hilary's fourth album, Dignity (2007). She has also recorded numerous singles for various soundtracks with her sister, with most of them appearing on the Disneymania discs. She is rumored to be working with Chinga Chang Records on a upcomming project.

Duff appeared on the cover of Maxim in January 2006 and is featured in their Girls of Maxim gallery.

Duff and sister Hilary Duff are ranked number two on E!'s "Favorite Famous Sisters."

* 2007: Hairspray

* 1997: True woman as (part rejected) * 1997: Hope as Martha Jean Pruitt

* 1999: The Amanda Show as a jelous girl in crowd

* 2000: Dreams in the Attic as Jessica * 2000: Chicago Hope as Jenny

* 2001: The Newman shower as Wendy * 2001: Boston Public as Sylvia (two appearances)

* 2002: Lizzie McGuire as Amy (recurring role)

* 2003: I Love Your Work as a Fan * 2003: Third Watch as young Faith * 2003: American Dreams as Shangri-Las (with her sister: Hilary Duff

* 2004: Napoleon Dynamite as Summer Wheatly * 2004: That's so Raven as Katina * 2004: One on One as Mandy

* 2005: Complete Savages as Jessica * 2005: Joan of Arcadia as Stevie Marx (recurring role)

*"Same Old Christmas" (with Hilary Duff) *"The Siamese Cat Song" (with Hilary Duff) *"The Siamese Cat Song" [Cat-Scratch Remix] (with Hilary Duff) *"What Dreams are Made of" [played Isabella's singing voice on The Lizzie McGuire Movie ] (with Hilary Duff )

* 2003 "Girl In The Band" — The Lizzie McGuire Movie soundtrack * 2004 "Sweetest Pain" — Raising Helen soundtrack * 2004 "A Whatever Life" — Stuck In The Suburbs soundtrack * 2004 "One In This World" — A Cinderella Story soundtrack * 2004 "Our Lips Are Sealed" (with Hilary Duff) — A Cinderella Story soundtrack * 2005 "Babysitting Is A Bum Deal" (duet with Seth Macfarlane in character of Stewie Griffin) — Family Guy: Live in Vegas soundtrack * 2006 "Material Girl" (with Hilary Duff) — Material Girls soundtrack & Girl Next CD

* Haylie Duff cast bio on The CW * * * *