Cynthia Jane Williams (August 22, 1947 – January 25, 2023) was an American actor. She is best known for her role as Shirley Feeney on the television sitcoms Happy Days (1975–1979), and Laverne & Shirley (1976–1982). She also appeared in American Graffiti (1973), The Conversation (1974), Mr. Ricco (1975), and More American Graffiti (1979).

Williams was born in Van Nuys, Los Angeles on August 22, 1947. Her mother Cindy was a waitress and her father Beachard "Bill" Williams worked at an electronics manufacturing company. The family moved to Dallas when she was a year old and returned to Los Angeles when she was ten years old. She had a sister named Carol Ann.^{[citation needed]}

Williams wrote and acted at a church during childhood and later acted in productions at Birmingham High School; she graduated in 1965, a year behind Sally Field. She attended Los Angeles City College where she majored in theater.

After college, Williams began her professional career by landing national commercials, which included Foster Grant sunglasses and TWA. Her first roles in television, among others, were on Room 222, Nanny and the Professor, and Love, American Style.

Williams accompanied an actor-friend from Los Angeles City College who needed a scene partner for the audition and was also accepted at The Actors Studio West, but rarely attended due to acting commitments. Williams picked up important film roles early in her career: George Cukor's Travels with My Aunt (1972); as Laurie Henderson, Ron Howard's character's high school sweetheart in George Lucas's American Graffiti (1973) for which she earned a BAFTA nomination as Best Supporting Actress; and Francis Ford Coppola's The Conversation (1974). She auditioned along with thousands of others, for Lucas's Star Wars for the role of Princess Leia, but Leia was ultimately played by Carrie Fisher because Lucas wished to cast unknowns, as in American Graffiti.

Williams met Penny Marshall, first on a double date, and later at Francis Ford Coppola's Zoetrope company. The company hired them as comedy writers, because "they wanted two women" on a prospective TV spoof for the Bicentennial. While the two were writing for Zoetrope, Penny Marshall's brother, Garry Marshall, called to ask if they would like to make an appearance on an episode of Happy Days, a television series he produced.

In 1975, Williams was cast as a fun-loving brewery bottle capper, Shirley Feeney, in an episode of Happy Days with Penny who played her best friend and roommate Laverne De Fazio. The girls were cast as "sure-thing" dates of Richie and Fonzie (Henry Winkler). Their appearance proved so popular that Garry Marshall commissioned a spin-off series for the characters of Shirley and Laverne. Williams continued her role on the very successful Laverne & Shirley series from 1976 until 1982. At one point during its run, the series was the number one rated show on television. Williams was praised for her portrayal of Shirley Feeney. She left the show after the second episode of the show's eighth and what would become its final season, after she became pregnant with her first child. The show's various producers were not enthusiastic that Williams was pregnant. Williams and co-star Penny Marshall had also been feuding for quite some time on the set long before Williams became pregnant. (They would reconcile many years later.) The success of the TV series led to a short-lived Saturday morning animated series Laverne & Shirley in the Army (1981–82), created by Hanna-Barbera.

In 1979, she reprised her role of Laurie from American Graffiti in its sequel, More American Graffiti.