"A Visit from St. Nicholas", more commonly known as "The Night Before Christmas" and "'Twas the Night Before Christmas" from its first line, is a poem first published anonymously in 1823 and later attributed to Clement Clarke Moore, who claimed authorship in 1837.

The poem has been called "arguably the best-known verses ever written by an American" and is largely responsible for some of the conceptions of Santa Claus from the mid-nineteenth century to today. It has had a massive impact on the history of Christmas gift-giving. Before the poem gained wide popularity, American ideas had varied considerably about Saint Nicholas and other Christmastide visitors. "A Visit from St. Nicholas" eventually was set to music and has been recorded by many artists.

On the night of Christmas Eve, a family are settling down to sleep when the father is disturbed by noises on the lawn outside. Looking out the window, he sees Saint Nicholas in an air-borne sleigh pulled by eight reindeer. After landing his sleigh on the roof, Saint Nicholas enters the house down the chimney, carrying a sack of toys. The father watches his visitor fill the stockings hanging by the fireplace, and laughs to himself. They share a conspiratorial moment before Saint Nicholas bounds up the chimney again. As he flies away, he wishes a "Happy Christmas to all, and to all a good night."