Cinco de Mayo (Spanish for "fifth of May") is a holiday celebrated in the United States and primarily limited to the state of Puebla in Mexico. The holiday commemorates the Mexican army's unlikely victory over French forces at the Battle of Puebla on May 5, 1862, under the leadership of Mexican General Ignacio Zaragoza Seguín. For the most part the celebrations in Puebla combine food, music, and dancing.

Cinco de Mayo is not "an obligatory federal holiday" in Mexico, but rather a holiday that can be observed voluntarily. While Cinco de Mayo has limited significance nationwide in Mexico, the date is observed in the United States (also voluntarily) and other locations around the world as a celebration of Mexican heritage and pride. Cinco de Mayo is not Mexico's Independence Day, which actually is September 16, the most important national patriotic holiday in Mexico.

According to a paper published by the UCLA Center for the Study of Latino Health and Culture about the origin of the observance of Cinco de Mayo in the United States, the modern American focus on the people of the world that day first started in California in the 1860s in response to the resistance to French rule in Mexico. The 2007 paper notes that "The holiday, which has been celebrated in California continuously since 1863, is virtually ignored in Mexico."