Family
- father Alex Cumming: Divorced from Cumming's mother; Cumming is estranged from his father and they haven't spoken since c. 1992
- mother : Divorced from Cumming's father
- brother Tom Cumming: Born c. 1959; has three children
Companions
- Companion Grant Shaffer: Met in 2004; married January 2007 in a civil ceremony in London
- Saffron Burrows: met during the filming of "Circle of Friends"; reportedly were engaged; no longer together as of 1996
- Nick: born in 1961; English; live together in NYC
- Companion Nick Philippou: Born c. 1961; in 2002 the two formed the production company The Art Party, which folded a year later; lived together in NYC; no longer together
