In 1835, Texas, which was then under the control of the Mexican Republic, rebelled against its overlords. Though there was a fierce debate among Texians as to whether they wanted to declare independence or simply force a return to the freer Mexican constitution of 1824, eventually the rebels did declare independence in March 1836, shortly before the rebellion ended.

The most famous episode of the conflict was the Battle of the Alamo when Texian soldiers fought for thirteen days against an onslaught of Mexican soldiers. Mexican General Santa Anna was determined to avenge Mexico's honor after Texian soldiers and an influx of American volunteers had forced all Mexican troops to retreat from Texas.

After a thirteen-day siege, Santa Anna's forces stormed the Alamo fortress, killing virtually all of the Texian defenders, including folk hero Davy Crockett. News of the Mexican savagery led to a massive surge in recruitment to the Texian Army and an increase in American volunteers, as well as a retreat and evacuation of Texian soldiers, civilians, and officials ahead of the advancing Mexican army.

Nevertheless, the battle created a strong sense of revenge among the new Texians, who defeated the Mexicans at the Battle of San Jacinto on April 21, ending the war. Mexico would never recognize an independent Texas. The new country was later annexed by the United States in 1845, leading to the Mexican–American War.