||This biographical article needs additional citations for verification, as its only attribution is to IMDb. (March 2009)|
|Born||Anthea Kym Karath
August 4, 1958
Los Angeles, California, U.S.
|Spouse(s)||Philippe L'Equibec (1985–2005)|
Karath started her career at the age of three, appearing in Spencer's Mountain with Henry Fonda and Veronica Cartwright in 1963 (she would subsequently work with Veronica's younger sister Angela Cartwright in The Sound of Music). Also in 1963, she was seen in The Thrill of It All with Doris Day and James Garner. In 1964, she was seen in Good Neighbor Sam with Jack Lemmon.
Karath is best remembered for her role in The Sound of Music, where she played the youngest child, Gretl Von Trapp.
During her appearance on The Ellen DeGeneres Show, Julie Andrews was asked about working with the Von Trapp children. She replied, "They were all lovely. However, the youngest one (Karath) was probably the most difficult for me, because she was just a tad heavy in those days. Today, she is this amazing gorgeous looking Monroe-esque young lady."
After The Sound of Music Karath primarily appeared in American television, including appearances in The Brady Bunch and Lost in Space. She remains friends with the other 'Von Trapp' children today, and in 2000 she went back to Salzburg with them, filming a documentary about the making of the film.
She is still currently working with them in new upcoming films.
Although Karath was born in Los Angeles, United States,  her family was actually Greek. Her original surname was Karathanasis, but then it was changed to Karath by her father. She has an older sister, Francie, who auditioned for the eldest Von Trapp child in The Sound of Music, a role that eventually went to Charmian Carr.
Karath graduated from the University of Southern California with a degree in Humanities, and shortly after that she moved to Paris, France where she studied art history and modeled as well. At the age of 26, she married Philippe L'Equibec; their son, Eric was born in 1991, thereafter she left acting for a while and lived in Greenwich, Connecticut, before resuming acting in 2005. 
- All My Children (1970) TV series as Kristen (unknown episodes, 1988)
- Midnight Offerings (1981) (TV) as Monique
- Archie Bunker's Place as Pretty Girl (1 episode, 1980)
- The Waltons as Mabel (1 episode, 1973)
- The Brady Bunch as Kerry Hathaway (1 episode, 1972)
- Family Affair as Barbara (3 episodes, 1966–1971)
- Lost in Space as Princess (1 episode, 1966)
- Lassie as Kathy Vaughn (1 episode, 1966)
- Dr. Kildare (2 episodes, 1966)
- My Three Sons as Pammy (1 episode, 1965)
- Peyton Place as Susan (1 episode, 1965)
- The Sound of Music (1965) as Gretl
- Good Neighbor Sam (1964) as Denise Bissel
- The Thrill of It All (1963) as Maggie Boyer
- Spencer's Mountain (1963) (uncredited) as Pattie-Cake Spencer