Winter Guard International (WGI) is an American performing arts association, governing body, and the producer of regional championship events for three activities: color guard (known as winter guard), percussion ensembles, and small marching bands (known as winds). WGI's competitive season is January to March, ending with an annual World Championships in April; hence, "winter" in the association's name.

WGI was founded in 1977 as a response to the inconsistent adjudication and incompatible rules of competition between various regional governing bodies and competition circuits which made it difficult for color guards to compete nationally. Today, WGI regularly publishes and updates an adjudication handbook, with an accompanying "Rules & Regulations", that has been adopted worldwide.

The first WGI World Championship for was held in 1978, then called WGI Olympics. World championships for percussion ensembles began in 1992, and winds in 2015. A series of fall marching band regional competitions, promoted as the WGI Friendship Cup, were hosted until 2003. The next World Championship series was previously scheduled for April 1 – April 4, 2020, for color guard; April 15 – April 18, 2020, for percussion ensembles; and April 18 – April 19, 2020 for winds. In March 2020, WGI announced all 2020 World Championship events would be cancelled, as would all remaining regional championship events, in response to the ongoing COVID-19 pandemic. The 2021 Season was held virtually.

A majority of WGI's championships are hosted in the United States, however regional championships have been frequently hosted in Japan, Malaysia, United Kingdom, Netherlands, and the Philippines and Costa Rica in 2018.