The Mexican-American War is an armed military conflict between the United States and Mexico from 1846 to 1848 in the wake of the 1845 U.S. annexation of Texas.

Mexico had not recognized the secession and subsequent military victory by Texas in 1836; it considers Texas a rebel province.In the United States, the conflict is traditionally referred to simply as the Mexican War.

In Mexico, it is referred to as La Intervención Norteamericana ("The North American Intervention"), La Invasión Estadounidense ("The United States Invasion"), La Guerra de Defensa ("The Defensive War"), or La Guerra del 47 ("The War of '47").