The Emerald City is the fictional capital of the Land of Oz in L. Frank Baum's Oz books, first described in The Wonderful Wizard of Oz.

According to early books in the series, the Wizard built the city and named it after himself, but later books indicate that he may

not have been its original founder, as some structures were there previously.

Located in the center of the Land of Oz, the Emerald City is the end of the famous yellow brick road, which starts in Munchkin Land. The Oz books describe the Emerald City as being completely green and comprised of green glass, emeralds, and other jewels. Even the people that live in the Emerald City are described as being green. Everyone in the Emerald City is made to wear green-tinted eyeglasses (in an effort to protect their eyes from the "brightness and glory" of the city), which explains why everything appears green, though this apparently changed under the rule of Princess Ozma.

Baum may have been partly inspired in his creation of the Emerald City by the White City of the World Columbian Exposition, which he visited frequently, having moved to Chicago in anticipation of the event. W. W. Denslow, the illustrator of The Wonderful Wizard of Oz, was also familiar with the White City, as he had been hired to sketch and document the exposition for the Chicago Herald; Denslow's illustrations of the Emerald City incorporate elements that may have been inspired by the White City.

Scholars who interpret ''The Wizard of Oz'' as a political allegory see the Emerald City as a metaphor for Washington, D.C. and unsecured "greenback" paper money. In this reading of the book, the city's illusory splendor and value is compared with the value of paper money, which also has value only because of a shared illusion or convention. It is highly likely that the Hotel del Coronado influenced its description in later books, as well as in the artwork by John R. Neill.

The Emerald City of Oz is the title of the sixth book in the Oz series.

In Gregory Maguire's revisionist Oz novels, Wicked: The Life and Times of the Wicked Witch of the West and Son of a Witch, the Emerald City is a much darker place than in Baum's novels. It does have splendid palaces and gardens, but also sections beset by crime and poverty. Son of a Witch introduces Southstairs, an extensive political prison located in the caves below the Emerald City.

David Williamson (whose brother-in-law wrote the Oz-inspired musical Oz) wrote a play in 1997 called Emerald City. The term is used as a metaphor by the character Elaine Ross, describing Sydney as "the Emerald City of Oz", where people go expecting their dreams to be fulfilled, only to end up with superficial substitutes and broken dreams.

The city of Seattle, Washington, of the United States uses "The Emerald City" as its official nickname, on account of how green it is in that region of the world. (Note: Washington State is also known as the "Evergreen State").