Family
- father Mark Fiennes: Remarried in 1996 after wife's death; collapsed suddenly and died in December 2004 at age 71
- mother Jini Fiennes: Died Christmas 1993 from breast cancer complications at age 54
- sister Martha Maria Fiennes: Directed her brother in the film "Onegin" (1999)
- brother Magnus Hubert Fiennes:
- sister Sophia Victoria Fiennes:
- brother Joseph Alberic Fiennes: Fraternal twin of Jacob; born in 1970; best known for starring in "Shakespeare in Love" (1998) and "Luther" (2003)
- brother Jacob Mark Fiennes: Fraternal twin of Joseph; born in 1970
- brother Michael Emery: Foster brother; family took him in when he was 11
Companions
- Companion Ellen Barkin: Rumored to be dating after being seen dinning out together in Fall 2006
- Francesca Annis: born on May 14, 1944; played Gertrude to Fiennes' Hamlet in 1994; had 20-year on again, off again relationship with photographer Patrick Wiseman with whom she had three children
