Farmer In The Sky is a 1950 science fiction novel by Robert Heinlein about a boy who emigrates to Jupiter's moon Ganymede, which is in the process of being terraformed, and who creates a farm out of gravel.

• June 1, 1973, Atheneum, library binding, ISBN 0684126486
• March 12, 1975, Ballantine Books, paperback, ISBN 0345243757
• March 12, 1978, Del Rey, paperback, ISBN 0345275969
• September 12, 1981, Del Rey, paperback, ISBN 0345302028
• February 12, 1985, Del Rey, paperback reissue edition, ISBN 0345324382
• December 2001, Books on Tape, cassette audiobook, ISBN 0736689354

In a future Earth where food is carefully rationed and Boy Scouts fly helicopters, a widower takes his son and new bride off-planet. After displaying heroics on the space ship, the boy is humiliatingly cut down to size by Scouts on his new home and struggles for acceptance. He volunteers to do the work of homesteading by himself, after his stepsister proves unable to live on the farm for health reasons.

First appearance (in Heinlein's novels) of the concept of ecology bringing on a war.