The architecture of Philadelphia is a mix of historic and modern styles that reflect the city's history. The first European settlements appeared within the present day borders of Philadelphia, Pennsylvania in the 17th century with most structures being built from logs. By the 18th century, brick structures had become common. Georgian and later Federal style buildings dominated much of the cityscape. In the first half of the 19th century, Greek revival appeared and flourished with architects such as William Strickland, John Haviland, and Thomas U. Walter. In the second half of the 19th century, Victorian architecture became popular with the city's most notable Victorian architect being Frank Furness.

Steel and concrete skyscrapers appeared in the first decades of the 20th century and glass and granite skyscrapers towards the end of the century. Construction continued into the 21st century with the city tallest building, the Comcast Center. Philadelphia made significant contributions in the architecture of the United States. The row house was introduced to the United States via Philadelphia in the 17th century, the United States' first International style skyscraper was built in Philadelphia, and one of the most important examples of Postmodern architecture, Robert Venturi's Guild House, is located in the city.