Family
- father Albert Hannigan: Divorced from Hannigan's mother c. 1975
- mother Emilie Posner: Divorced from Hannigan's father c. 1975
- daughter Satyana Denisof: Born on her mother's birthday, March 24, 2009; father, Alex Denisof
Companions
- Alex Denisof: born c. 1966; also appeared on "Buffy the Vampire Slayer"; dating from early 2000; engaged as of December 2002
- Ginger Fish: drummer with Marilyn Manson; ended relationship c. late 1999
