Family
- father Mark Fiennes:
- mother Jini Fiennes: Died Christmas 1993 from breast cancer complications at age 54
- brother Ralph Fiennes: Born Dec. 22, 1962
- sister Martha Fiennes: Older
- brother Magnus Hubert Fiennes: Older
- sister Sophie Victoria Fiennes: Older
- brother Jacob Mark Fiennes: Fraternal twin of Joseph; born May 27, 1970
- brother Michael Emery: Foster brother; moved in with the Fiennes family when he was 11
Companions
- Catherine McCormack: dated in summer 1999
- Fiona Jolly: dating as of 2001
- Naomi Campbell: reportedly involved in 2000
- Natalie Imbruglia: dated briefly in late 1999
- Sara Griffiths: together from c. 1992 to 1998
- Companion Maria Dolores: Dating as of 2007
