Diff'rent is a two-act tragedy written by American playwright Eugene O'Neill. The story concerns a woman who rejects her fiancée over a single act of infidelity and later becomes engaged to another man who turns out to have poor character. The first man commits suicide, and she regrets her choice.

The play premiered in 1921 at the Princess Theatre on Broadway, when theatres reopened following closures due to the Spanish flu. Captain Caleb was played by James Light in the original 1921 production.

A second production ran on Broadway in 1938.

The Spanish flu ended officially in 1920, the year before the play premiered and for the year that Act II of the play is taking place. World War I had ended three years earlier, in 1918.

The Roaring Twenties was at its dawn. Flapper became a new word in the U.S. vocabulary, which according to Webster's Dictionary was "a young girl, esp. one somewhat daring in conduct, speech and dress,".

Young women in the audience may have seen a world in 1921 where the men who were possible candidates for marriage were tending to be either older or younger than the women seeking husbands. It was known at the time that the Spanish Flu and World War I had altered the U.S. gender ratio, with more young women being in the population than young men, for the age range of 20–40. This was largely due to the Spanish Flu having increased the mortality rates for men from 20 to 40. Like COVID, the Spanish Flu caused people to stay isolated in their homes. The end of the pandemic allowed people to socialize again.

The title of the show Diff'rent makes use of the way people speak in the village. Making use of the way a certain community spoke was a device often used in O'Neill plays.

Setting: The parlor of home on a side street of a seaport village in New England in 1890.