A fashion week is a fashion industry event, lasting approximately one week, where fashion designers, brands or "houses" display their latest collections in runway fashion shows to buyers and the media. These events influence the upcoming fashion trends for the current and approaching seasons.

The most prominent fashion weeks are held in the fashion capitals of the world— in chronological order, New York City, London, Milan, and Paris, or the "Big Four", with exquisite fashion heritage, structured organization, and the most vaunted fashion designers of the last century, the four cities considered the main fashion capitals of the 21st century, and which receive the majority of press coverage.

During 2010s, fashion globalization contributed significantly to the rise of non-traditional fashion cities to significant relevance in the fashion calendar, in addition to the Big Four, other notable fashion weeks are held in Berlin, Madrid, Shanghai, São Paulo, and Tokyo.