The Mexican War of Independence (Spanish: Guerra de Independencia de México) was an armed conflict, and the culmination of a political and social process which ended the rule of Spain in 1821 in the territory of New Spain. The war had its antecedent in Napoleon's French invasion of Spain in 1808; it extended from the Cry of Dolores by Father Miguel Hidalgo y Costilla on September 16, 1810, to the entrance of the Army of the Three Guarantees led by Agustín de Iturbide to Mexico City on September 27, 1821. September 16 is celebrated as Mexican Independence Day.

The movement for independence was inspired by the Age of Enlightenment and the American and French Revolutions. By that time the educated elite of New Spain had begun to reflect on the relations between Spain and its colonial kingdoms. Changes in the social and political structure occasioned by Bourbon Reforms and a deep economic crisis in New Spain caused discomfort among the native-born Creole elite.

The dramatic political events in Europe, the French Revolutionary Wars and the conquests of Napoleon deeply influenced events in New Spain. In 1808, Charles IV and Ferdinand VII were forced to abdicate in favor of the French Emperor, who then made his elder brother Joseph king. The same year, the ayuntamiento (city council) of Mexico City, supported by viceroy José de Iturrigaray, claimed sovereignty in the absence of the legitimate king. That led to a coup against the viceroy; when it was suppressed, the leaders of the movement were jailed.