Family
- sister Haylie Duff: Older; member of music group inventing venus
- mother Susan Duff:
- father Bob Duff:
Companions
- Companion Aaron Carter: Dated c. 2003, resulting in a high profile feud between Duff and actress Lindsay Lohan, who had also dated Carter; no longer together
- Companion Jordy Masterson: Brother of actor Danny Masterson; briefly dated in January 2004
- Companion Joel Madden: Lead singer of the band "Good Charlotte"; began dating July 2004; split November 2006
- Companion Mike Comrie: Canadian; dating c. 2007
