The Mexican War of Independence (Spanish: Guerra de Independencia de México) was an armed conflict result of a political and social process which ended the rule of Spain in the territory of New Spain. The war had it antecedent in the French invasion of Spain in 1808 and extended from the Grito de Dolores on September 16 of 1810, to the entrance of the Army of the Three Guarantees to Mexico City on September 27 of 1821.

The movement was caused in part by the Age of Enlightenment and the liberal revolutions of the last part of the 18th century. By that time the educated elite of the current Mexico began to reflect about the relations between Spain and its colonial kingdoms. Changes in the social and political structure caused by Bourbon reforms and a deep economic crisis in New Spain, caused discomfort mainly in the Creole population.

In 1808 the king Charles IV and Ferdinand VII abdicated to Napoleon Bonaparte, who left the crown of Spain to his brother Joseph Bonaparte. The same year, the ayuntamiento of Mexico city, supported by viceroy José de Iturrigaray, claimed sovereignty in the absence of the legitimate king, the reaction led to a coup against the viceroy and led the leaders of the movement to jail.

Despite the defeat in Mexico City, small groups of conspirators met in other cities of New Spain in order to follow the steps of Mexico City. In 1810, after being discovered, Querétaro conspirators chose to take up arms on September 16 in the company of peasants and indigenous inhabitants of the town of Dolores (Guanajuato), called by the priest Miguel Hidalgo y Costilla.

Since 1810, the independence movement went through several stages, as its leaders were imprisoned or executed by loyal forces to Spain. At first they claimed sovereignty of Ferdinand VII over Spain and its colonies, but after the leaders took more radical positions, including issues of social order as the abolition of slavery. José María Morelos called the separatist provinces to form theCongress of Chilpancingo, which gave the insurgency of its own legal framework. After the defeat of Morelos, the movement was reduced to a guerrilla war. By 1820, there were only some rebel groups, especially in the Sierra Madre del Sur and Veracruz.

The reinstatement of the Constitution of Cadiz in 1820 caused a change of the elites who supported the Spanish rule. The monarchists Creoles which the Constitution affected in their interests, decided to support the independence of New Spain and they sought to ally with the old insurgent resistance. Agustín de Iturbide led the military arm of the conspirators and early 1821 he could met with Vicente Guerrero. Both proclaimed the Plan of Iguala, which called the union of all insurgent factions and it had the support of the aristocracy and the clergy of New Spain. Finally, the independence of Mexico was consummated on September 27, 1821.

After that, the mainland of New Spain became the Mexican Empire, an ephemeral catholic monarchy which became a federal republic in 1823, between internal conflicts and the separation ofCentral America.

After some Spanish reconquest attempts, including the expedition of Isidro Barradas in 1829, Spain under the rule of Isabella II recognized the independence of Mexico in 1836.