The buildings and architecture of Chicago reflect the city's history and multicultural heritage, featuring prominent buildings in a variety of styles. Most structures downtown were destroyed by the Great Chicago Fire in 1871 (an exception being the Water Tower).

Chicago's architectural styles include the Chicago School primarily in skyscraper design, Chicago Bungalows, Two-Flats, and Greystones. The Loop is home to skyscrapers as well as sacred architecture including "Polish Cathedrals". Chicago is home to one of the largest and most diverse collections of skyscrapers in the world.

Beginning in the early 1880s, architectural pioneers of the Chicago School explored steel-frame construction and, in the 1890s, the use of large areas of plate glass. These were among the first modern skyscrapers. William LeBaron Jenney's Home Insurance Building was completed in 1885 and is considered to be the first to use steel in its structural frame instead of cast iron. However, this building was still clad in heavy brick and stone. The Montauk Building, designed by John Wellborn Root Sr. and Daniel Burnham, was built from 1882 to 1883 using structural steel. Daniel Burnham and his partners, John Welborn Root and Charles B. Atwood, designed technically advanced steel frames with glass and terra cotta skins in the mid-1890s, in particular the Reliance Building; these were made possible by professional engineers, in particular E. C. Shankland, and modern contractors, in particular George A. Fuller.

Louis Sullivan discarded historical precedent and designed buildings that emphasized their vertical nature. This new form of architecture, by Jenney, Burnham, Sullivan, and others, became known as the "Commercial Style," but was called the "Chicago School" by later historians.

In 1892, the Masonic Temple surpassed the New York World Building, breaking its two-year reign as the tallest skyscraper, only to be surpassed itself two years later by another New York building.

Since 1963, a "Second Chicago School" has emerged from the work of Ludwig Mies van der Rohe at the Illinois Institute of Technology in Chicago. The ideas of structural engineer Fazlur Khan were also influential in this movement. He introduced composite construction to tall tubular buildings, which in turn paved the way for the creation of supertall composite buildings such as Petronas Towers and the Jin Mao Building since the 1960s.

Numerous architects have constructed landmark buildings of varying styles in Chicago. Among them are the so-called "Chicago seven": James Ingo Freed, Tom Beeby, Larry Booth, Stuart Cohen, James Nagle, Stanley Tigerman, and Ben Weese. Daniel Burnham led the design of the "White City" of the 1893 World's Columbian Exposition which some historians claim led to a revival of Neo-Classical architecture throughout Chicago and the entire United States. Burnham developed the 1909 "Plan for Chicago" in a Neo-Classical style, although many skyscrapers were built after the Exposition closed, between 1894 and 1899. Louis Sullivan said that the fair set the course of American architecture back by two decades, but his work the Schlesinger and Meyer (later Carson, Pirie, Scott) store was built in 1899—five years after the "White City" and ten years before Burnham's Plan.

Erik Larson's history of the Columbian Exposition, The Devil in the White City, says that the building techniques developed during the construction of the many buildings of the fair were entirely modern, even if they were adorned in a way Sullivan found aesthetically distasteful.^{[full citation needed]}