The Second French Intervention in Mexico (Spanish: Segunda intervención francesa en México), also known as the Second Franco-Mexican War, 1861–1867; was an invasion of Mexico, launched in late 1862, by the Second French Empire, aimed at regime change in Mexico, hoping to replace the Mexican Republic with a monarchy favorable to French interests.

After President Juarez placed a moratorium on foreign debt payments in 1861, France, the United Kingdom, and Spain agreed to the Convention of London, a joint effort to ensure that debt repayments from Mexico would be forthcoming. On 8 December 1861, the three navies disembarked their troops at the port city of Veracruz, on the Gulf of Mexico. However, when the British discovered that France had an ulterior motive and unilaterally planned to seize Mexico, Britain separately negotiated an agreement with Mexico to settle the debt issues and withdrew from the country. Spain subsequently left as well. The resulting French invasion established the Second Mexican Empire (1862–1867). Many European nations acknowledged the political legitimacy of the newly created nation state, while the United States refused to recognize it.The intervention came as a civil war, the War of Reform, had just concluded, and the intervention allowed the opposition against the liberal social and economic reforms of president Benito Juárez (1858–1872) to take up their cause once again, thus the Mexican Catholic Church, upper-class conservatives, much of the Mexican nobility, and some Native American communities welcomed and collaborated with the French empire's installation of Maximilian von Habsburg as Emperor of Mexico. The emperor himself, however proved to be of liberal inclination and continued some of the Juarez' government's most notable liberal measures. Some liberal generals defected to the Empire, and even Governor Santiago Vidaurri who had fought on the side of Juarez during the War of Reform became a supporter of the Empire.

The French rapidly captured much of the nation, and its major cities, but guerrilla warfare remained rampant, and the intervention was increasingly using up troops and money at a time when the recent Prussian victory over Austria was inclining France to have more military priority in Europe. The liberals also never lost the official recognition, and after the end of the Civil War in 1865, the material support of the United States. The American government made it clear in accordance with the Monroe Doctrine that it would not tolerate a French presence on the continent and the French finally began to leave in 1866. The Empire would last a few more months and subsequently, the Juarez government executed Emperor Maximilian I with his two leading Mexican generals, on 19 June 1867, and restored the Mexican Republic.