The Mexican Empire was a constitutional monarchy, the first independent government of Mexico and the only former colony of the Spanish Empire to establish a monarchy after independence. It is one of the few modern-era, independent monarchies that have existed in the Americas, along with the Brazilian Empire. It is typically denominated as the First Mexican Empire to distinguish it from the Second Mexican Empire.

Agustín de Iturbide, the sole monarch of the empire, was originally a Mexican military commander under whose leadership independence from Spain was gained in September 1821. His popularity culminated in mass demonstrations on 18 May 1822, in favour of making him emperor of the new nation, and the very next day congress hastily approved the matter. A sumptuous coronation ceremony followed in July.

The empire was plagued throughout its short existence by questions about its legality, conflicts between congress and the emperor, and a bankrupt treasury. Iturbide dissolved the congress in October 1822, replacing it with a junta of supporters, and by December of that year had begun to lose support of the army, which revolted in favor of restoring congress. After failing to put down the revolt, Iturbide reconvened congress in March 1823, and offered his abdication, upon which power passed to a provisional government which ultimately abolished the monarchy.