Mariska Magdolna Hargitay (/məˈrɪʃkə ˈhɑːrɡɪteɪ/; born January 23, 1964) is an American actress, philanthropist, producer, and director. Hargitay has starred as Olivia Benson on NBC's Law & Order: Special Victims Unit since 1999, making it the longest-running character in American primetime drama in history. Her accolades for the role include an Emmy and a Golden Globe. In 2013, she received a star on the Hollywood Walk of Fame.

Hargitay was born in Santa Monica, California, and is a daughter of actress Jayne Mansfield. She attended Marymount High School in Los Angeles and enrolled in the UCLA School of Theater, Film and Television, leaving before completing her degree to pursue acting. Her other credits include the series Falcon Crest and In the Heat of the Night (both 1988), Tequila and Bonetti (1992), Can't Hurry Love (1995–1996), and ER (1997–1998).

Outside of acting, Hargitay co-produced the HBO documentary I Am Evidence (2017), winning a News and Documentary Emmy for the project. In 2025, she launched the production company Mighty Entertainment, under which she directed the documentary My Mom Jayne. Hargitay founded the Joyful Heart Foundation, which provides support to people who have been sexually abused. She is a certified rape counselor and has engaged in initiatives to support domestic violence shelters and raise awareness about untested rape kits.

Mariska Magdolna Hargitay was born at Providence Saint John's Health Center in Santa Monica, California, to actress Jayne Mansfield. The biological father was later found to be singer Nelson Sardelli. She was conceived during her mother's marriage to Mickey Hargitay, so he was the legal father, and Mariska grew up believing he was her biological father as well. Her first and middle names are Hungarian and refer to Mary Magdalene (Mariska is a diminutive of Mary). She was raised Catholic. Jayne Mansfield had four other children: Jayne Marie Mansfield, Miklós "Mickey" Hargitay, Jr., Zoltán Hargitay, and Antonio "Tony" Cimber.

In 1962, troubles arose in Mansfield and Hargitay's marriage after Mansfield had an affair with an Italian filmmaker. Mansfield and Hargitay divorced in May 1963, but a judge later found their Mexican divorce invalid. After Mansfield realized she was pregnant with Mariska, she and Hargitay reconciled in January 1964. However, they soon separated again. In August 1964, Hargitay's mother successfully petitioned the court to rule the Mexican divorce legal.

On June 29, 1967, Mariska, her mother, and Mansfield's boyfriend Sam Brody were in an automobile crash on a stretch of U.S. Route 90 between New Orleans and Bay St. Louis, Mississippi. The accident ripped off the top of the car, instantly killing Mansfield, Brody, and the driver, Ronnie Harrison. Asleep in the back of the vehicle, three-and-a-half-year-old Mariska and her brothers, Miklós and Zoltán, escaped with minor injuries. The accident left Mariska with a zig-zag scar on her head.

After the death of their mother, Hargitay and her brothers were raised by Mickey Hargitay and his third wife, Ellen Siano. Hargitay dislikes comparisons with her famous mother and, at age 18, said, "My dad was Mr. Universe, so it would be fun for me to be Miss Universe." Hargitay has said that the early loss of her mother left "a hole in my life that won't ever be filled. I will never get over it. I will always be a girl who lost her mom."

While a student at her Catholic secondary school, Marymount High School, Hargitay was active in cheerleading, student government, athletics, and the theater program. She enjoyed acting and enrolled at UCLA after graduation from high school in 1982. That same year, Hargitay was crowned Miss Beverly Hills USA. By the time she was a freshman in college, Hargitay had an agent and several small roles to her credit. She attended UCLA School of Theater Film and Television where she was a member of Kappa Kappa Gamma. She left before completing her degree. Hargitay attended Groundlings Theatre and School in Los Angeles.