Cinco de Mayo (Spanish for "fifth of May") is a holiday held on May 5. It is celebrated nationwide in the United States and regionally in Mexico, primarily in the state of Puebla. The date is observed in the United States as a celebration of Mexican heritage and pride, and to commemorate the cause of freedom and democracy during the first years of the American Civil War. In the state of Puebla, the date is observed to commemorate the Mexican Army's unlikely victory over French forces at the Battle of Puebla on May 5, 1862, under the leadership of General Ignacio Zaragoza Seguin. Contrary to widespread popular belief, Cinco de Mayo is not Mexico's Independence Day, the most important national patriotic holiday in Mexico, which occurs on September 16th.

Events tied to Cinco de Mayo also occur outside Mexico and the United States. For example, a sky-diving club near Vancouver, Canada, holds a Cinco de Mayo skydiving event. In the Cayman Islands, in the Caribbean, there is an annual Cinco de Mayo Air Guitar competition. As far away as the island of Malta, in the Mediterranean Sea, revelers are encouraged to drink Mexican beer on May 5.