Sylvia Anderson (née Thamm) (born 25 March 1937) is a British voice artist and producer, most notable for her collaborations with her ex-husband Gerry Anderson. She created the characters for several of the series, co-wrote episodes, voiced female roles in many series, most memorably Lady Penelope in the Thunderbirds television series and subsequent films, and was most influential in the creation of Captain Scarlet and The Mysterons. The couple married in 1960 and were divorced in 1980 following a 5-year separation.

As Sylvia Thamm, she and Gerry Anderson met when they both worked for Polytechnic films, she as a secretary, he as an editor/director. When Anderson and his colleague Arthur Provis created AP Films following the collapse of Polytechnic in 1957, Sylvia followed them in company with John Read and Reg Hill. She became Anderson's second wife shortly after, in 1960, and slowly became involved in production duties.

The creative partnership with Gerry Anderson concluded when their marriage broke down during the production of the first series of Space: 1999 in 1975; Gerry announced his intention to separate on the evening of the wrap party, following which Sylvia severed her ties with the production company.

Unlike her former husband, Sylvia Anderson tends to avoid the limelight, although she has written an autobiography titled Yes M'Lady Yes M'Lady by Sylvia Anderson; ISBN 1-85685-011-0 covering the Thunderbirds era. Until recently, Sylvia worked as the UK representative for HBO and her new book, My Fab Years was published in 2007.

Sylvia Anderson is the co-creator of a string of hit TV shows through the late 1950s, 1960s and 70s. Her most memorable contribution as an actress is the voice of Lady Penelope from Thunderbirds - one of many series she co-created with former husband Gerry Anderson. Sylvia's talents are evident in the characterization throughout their various series. She was against Martin Landau and Barbara Bain being cast in "Space: 1999" (1975) but was overruled by ITC chief Lew Grade. The forgotten heroine of Britain's famous TV shows, she's had to watch former husband Gerry take most of the limelight over the years. A fascinating woman with overwhelming talent, she now represents the American network HBO in Pinewood Studios in London, England.