Based on the 1971 novel by Avery Corman, the film was directed by Carl Reiner from a screenplay by Larry Gelbart.

The story centers on supermarket manager Jerry Landers (Denver), who is chosen by God (Burns) to spread his message despite skepticism of the media, religious authorities, and his own wife (Teri Garr).

Landers tells his wife, children and a religion editor of the Los Angeles Times of his encounters with God and becomes a national icon of comedic fodder.

The next day, after Jerry is stranded from a car breakdown, God appears as a taxi driver to take him home, where they are met by a bunch of chanting "religious nuts".

They challenge him to answer a series of questions in Aramaic while locked in a hotel room alone, to prove God is contacting him directly.

He argues that if God's existence is a reasonable possibility, he can materialize and sit in the witness chair if he chooses.

Jerry argues that when everyone waited a moment to see what would happen when he raised the mere possibility of God appearing, it proved he at least deserved the benefit of the doubt.

Jerry expresses worry that they failed, but God compares him to Johnny Appleseed, saying he was given the best seeds and they will take root.

Roger Ebert gave the film 3.5 stars out of possible 4, praising the casting of Burns and Denver and noting that Oh God!

's Biblical playfulness makes for more cute farce than divine comedy, but George Burns' sly performance as the Almighty gives this high concept gravitas".