Kim Diane McGuire (December 1, 1955 – September 14, 2016) was an American lawyer and author. A former actress, she was best known for her role of Mona "Hatchet-Face" Malnorowski in John Waters' 1990 comedy musical Cry-Baby.

McGuire continued to work in films over the next few years, with appearances in a TV movie, Acting on Impulse (1993); and an uncredited cameo in John Waters' next project, Serial Mom (1994). Her unusual appearance was also put to memorable use in two off-beat television series, each featuring odd characters in quirky scenarios: the HBO series Dream On (1990) and David Lynch's short-lived On the Air (1992), which was cancelled after only three episodes. In December 1997, she was admitted to the California State Bar and began working as an attorney in Los Angeles, specialising in entertainment and appellate law. She and her husband, Emmy-winning television producer Gene Piotrowsky, were in New York at the time of the September 11 attacks and consequently found themselves unemployed. The couple moved to Biloxi, Mississippi. In September 2005, McGuire and Piotrowsky were rendered homeless by Hurricane Katrina.

By November 2005, McGuire had become temporarily licensed to practice law in Alabama, and subsequently resumed her career as an attorney, specialising in family law. She was admitted to the Alabama State Bar in September 2006, and re-admitted to the California State Bar in April 2010 after a period of professional inactivity in that state.

On September 13, 2016, McGuire was admitted to the ICU at Physicians Regional Hospital in Naples, Florida with pneumonia. After failing to respond to treatment, she suffered a cardiac arrest and died the following day.