Jack Warner Schaefer (November 19, 1907 – January 24, 1991) was a twentieth-century American author known for his Westerns. His most famous work is Shane, which was made into a critically acclaimed movie, and the short story "Stubby Pringle's Christmas" (1964).

Jack Warner Schaefer was born in Cleveland, Ohio, the son of an attorney. He graduated from Oberlin College in 1929 with a major in English. He attended graduate school at Columbia University from 1929–30, but left without completing his Master of Arts degree. He then went to work for the United Press. In his long career as a journalist, he would hold editorial positions at many eastern publications.

Schaefer's first success as a novelist came in 1949 with his memorable novel Shane, set in Wyoming. Few realized that Schaefer himself had never been anywhere near the west. Nevertheless, he continued writing successful westerns, selling his home in Connecticut and moving to Santa Fe, New Mexico in 1955.

In 1975 Schaefer received the Western Literature Association's Distinguished Achievement award.

He died of heart failure in Santa Fe in 1991. Schaefer was married twice, his second wife moving to Santa Fe with him.

Schaefer's novel Monte Walsh was made into a movie in 1970, with Lee Marvin in the title role, and again in 2003 as a TV movie starring Tom Selleck. Shane was also made into a movie and a series.

This unforgettable story of the friendship between a farm boy and a gunman struggling to escape his dark past was made into a critically acclaimed movie in 1953 which became a classic standard for Westerns. Shane, a mysterious traveller and ex-gunfighter, enters into the life of Joe Starrett and his family and carves a place for himself in their hearts. Although he tries to leave his gunslinging past behind, revealing little about himself and refusing to even carry a gun, the family senses a quiet tension about him like a slow burning fuse. In the end, he decides to fight Fletcher and Wilson, the town enemies, in order to break the power of the cattlemen over the homesteaders and save Joe Starrett's farm. The story is told through the eyes of young Bob Starett, who regards Shane with an awe and reverence tempered by the boyishness of the Old West.

''A gun is a tool, Marian; no better or no worse than any other tool: an axe, a shovel or anything. A gun is as good or as bad as the man using it. Remember that.''--Shane