Nancy Laura Spungen (February 27, 1958 - October 12, 1978) was the controversial girlfriend of Sex Pistols' bassist Sid Vicious.

Nancy was born to a middle class Jewish family in Pennsylvania, USA. However she had trouble in her teens, being highly hyperactive. At eleven she was already being administered intense psychotherapy. She tried killing herself numerous times and suffered severe depression.

In later years (according to her mother, who refers to Nancy's medical records in her book about her daughter) it would emerge that Nancy suffered from paranoid schizophrenia, however this is rarely publicised in relation to Nancy's "anti-social" behaviour. Thus it would seem that there is much evidence that her inability to empathise with others was due to mental illness.

Nancy left home at age 19 and became a groupie, following such bands as Aerosmith, The New York Dolls, and The Ramones. She moved to London with the express purpose of winning over one of the New York Dolls, but found The Sex Pistols instead. She met bassist Sid Vicious at a friend's apartment. They quickly moved in together.

During a rocky 21-month relationship Spungen and Vicious abused heroin and other drugs. Spungen's difficult personality (the tabloids dubbed her "Nauseating Nancy" for her frequent, public displays of drug-fueled verbal abuse and violence) and Vicious's emotional dependence on her proved problematic to the Sex Pistols' performances and contributed to the band splitting up during their US tour. Spungen and Vicious moved to the famous Hotel Chelsea in New York City where Vicious tried, with little success, to revive his musical career.

With increased drug abuse and reports of domestic violence, the pair seemed destined for a tragic end. That end came on October 12, when Spungen was found in a black bra and panties, having bled to death from a stomach wound that was traced to Vicious's knife. Vicious was arrested for the murder, but died of a heroin overdose on February 2, 1979 while out on bail.

Spungen's and Vicious's nontraditional romance was the subject of an off-Broadway play as well as the 1986 Alex Cox film Sid and Nancy.

Literary work about Nancy Spungen

• And I Don't want to Live this Life (Deborah Spungen, Nancy's mother, 1983).