The Centralist Republic of Mexico, or in the anglophone scholarship, the Central Republic, officially the Mexican Republic, was a unitary political regime established in Mexico on 23 October 1835, under a new constitution known as the Siete Leyes after conservatives repealed the federalist Constitution of 1824 and ended the First Mexican Republic. It would ultimately last until 1846, when the Constitution of 1824 was restored at the beginning of the Mexican-American War.

The First Mexican Republic, known also as the First Federal Republic, existed from 1824 to 1835. It was a federated republic, established by the Constitution of 1824, the first constitution of independent Mexico, and officially designated the United Mexican States. It ended in 1835, when conservatives under Antonio López de Santa Anna transformed it into a unitary state, the Centralist Republic of Mexico.