"It's Such a Small World" is a duet by American country music artists Rodney Crowell and Rosanne Cash, released in January 1988. "It's Such a Small World" was the lead-off single to Crowell's Diamonds and Dirt album, which charted five No. 1 hits in between 1988 and 1989.

The song tell the story of two former lovers (or former spouses) who meet by chance in New York City, after having not seen one another in many years. They begin to reminisce, and eventually end up spending the night together. As this is happening, however, they are both clear that it is only a one-night-fling (and a chance to share one more time what they once had togheter), and not a renewal of their affair.