The first filmed version was made in 1919 by the Famous Players-Lasky Corporation with 17-year-old Lila Lee as Mary and Paul Willis as Dickon, but the film is thought lost.
In 1949, MGM filmed the second adaptation with Margaret O'Brien as Mary, Dean Stockwell as Colin and Brian Roper as Dickon. This version was mostly in black-and-white, but the sequences set in the restored garden were filmed in Technicolor.
Dorothea Brooking adapted the book into several different television serials for the BBC: an eight-part serial in 1952, an eight-part serial in 1960 (starring Colin Spaull as Dickon). The seven-part TV serial made by the BBC in 1975 has been released on DVD.
Barbara Sleigh's Jessamy (1967) is reading the book on the train as the novel begins.
In 1987, Hallmark Hall of Fame filmed a TV adaptation of the novel starring Gennie James as Mary, Barret Oliver as Dickon, and Jadrien Steele as Colin. Billie Whitelaw as Mrs Medlock Derek Jacobi played the role of Archibald Craven, with Alison Doody appearing in flashbacks and visions as Lilias; Colin Firth made a brief appearance as the adult Colin Craven. It was filmed at Highclere Castle which later became known as the filming location for Downton Abbey
American Zoetrope's 1993 production was directed by Agnieszka Holland screenplay by Caroline Thompson and starred Kate Maberly as Mary, Heydon Prowse as Colin, Andrew Knott as Dickon and Dame Maggie Smith as Mrs. Medlock. Other credits include; Executive Producer Francis Ford Coppola
A 1994 animated adaptation as an ABC Weekend Special starred Honor Blackman, Sir Derek Jacobi, Glynis Johns, Victor Spinetti, Anndi McAfee as Mary Lennox, Joe Baker as Ben Weatherstaff, Felix Bell as Dickon, Naomi Bell as Martha, Richard Stuart as Colin, and Frank Welker as Robin.
In Japan, NHK produced and broadcast an anime adaptation of the novel in 1991–1992 titled Anime Himitsu no Hanazono (アニメ ひみつの花園). Miina Tominaga was featured as the voice of Mary, while Mayumi Tanaka voiced Colin. The 39-episode TV series was directed by Tameo Kohanawa and written by Kaoru Umeno. Based on the title, this anime is sometimes mistakenly assumed to be related to the popular dorama series Himitsu no Hanazono. Surprisingly unavailable in the English language, it has been dubbed into several other languages including Spanish, Italian, Polish, and Tagalog.
Stage adaptations of the book have also been created. In 1991, a musical version opened on Broadway, with music by Lucy Simon, and book and lyrics by Marsha Norman. The production was nominated for seven Tony Awards, winning Best Book of a Musical and Best Featured Actress in a Musical for Daisy Eagan as Mary, then eleven years old. In 2013, an opera by the American composer Nolan Gasser which had been commissioned by the San Francisco Opera premiered at the Zellerbach Hall at the University of California, Berkeley.
A stage play by Jessica Swale adapted from the novel was performed at Grosvenor Park Open Air Theatre in Chester 2014.
A multimedia web series adaptation of the novel titled The Misselthwaite Archives was released on YouTube in January 2015 and is currently ongoing.