For years after the release of How Green Was My Valley, John Ford gave regular parties for a group he called the Ladies of the Green Valley, including female cast members Maureen O'Hara and Anna Lee, along with writer Philip Dunne and actor Roddy McDowall. He also included Jane Darwell, who had won an Oscar® for his The Grapes of Wrath (1940) and whom he privately wished had played Sara Allgood's role.

A one-hour version of the film was broadcast on Lux Radio Theater in 1942 with Walter Pidgeon, Donald Crisp, O'Hara, McDowall and Allgood repeating their roles. Crisp would return for new versions in 1947 and 1954. The Screen Guild Theater did a 30-minute version in 1942 with the same cast members and Rhys Williams.

The film's title was spoofed in the 1950 Popeye cartoon "How Green Is My Spinach."

Richard Llewellyn wrote three sequels to the novel, Up into the Singing Mountain (1960), about Huw's emigration to Argentina; Down Where the Moon Is Small (1966), about his life there, and Green, Green My Valley Now (1975), about his return to Wales. None matched the original's popularity.

The novel has twice been turned into miniseries for the BBC. The 1960 version ran four hours and starred Eynon Evans and Rachel Thomas as Mr. and Mrs. Morgan. In 1975, it ran five hours and starred Stanley Baker and Sian Phillips as the parents, Gareth Thomas as Mr. Gruffyd and Dominic Guard as Huw Morgan.

A stage musical adapted from the novel, A Time for Singing, flopped in 1966. John Morris wrote the music and collaborated with Gerald Freedman on the book and lyrics. The cast included Laurence Naismith as Gwilym, Tessie O'Shea as Beth, Shani Wallis as Angharad, George Hearn as Ianto and Elizabeth Hubbard as Bronwyn.

The title was parodied in an episode of House in which one of the characters was watching a porno film called How Wet Was My Valley. In fact, a hardcore sex film of that same title was released to adult theatres in the seventies.

by Frank Miller