Family
- father Alexander Rae Baldwin Jr: Taught high school history and coached football in Massapequa New York; died of lung cancer in 1983
- mother Carol Newcomb Baldwin: Born in 1930; breast cancer survivor
- sister Elizabeth Baldwin: Born c. 1955; non-acting mother of six and head of Stephen Baldwin's fan club; married to landscaper Charles Keuchler
- brother Daniel Baldwin: Born in 1960; best known for playing Det. Beau Felton on NBC's "Homicide: Life on the street"
- brother William Baldwin: Born in 1963; married to singer-actress Chynna Phillips; best known for starring in "Backdraft" (1991), "Sliver" (1993) and ABC's "Dirty Sexy Money
- sister Jane Baldwin: Born c. 1965; married to car dealership manager Randy Sasso
- brother Stephen Baldwin: Born in 1967; married to graphics designer Kennya Deodato Baldwin; known for "The Usual Suspects" (1995) and "Bio-Dome"; became a born-again Christian in the Evangelical church shortly after the September 11 attacks
- daughter Ireland Eliesse Baldwin: Born Oct. 23, 1995; mother, Kim Basinger
Companions
- Holly Gagnier: together in the mid-1980s
- Janine Turner: engaged c. 1983; wedding cancelled
- wife Kim Basinger: met while filming "The Marrying Man" in 1990; married on August 19, 1993; separated on December 5, 2000; filed for divorce in January 2001
- Kristin Davis: dated in summer 2001
- Tatum O'Neal: reportedly began dating in spring 2002
