The Presidential Republic is the period in the History of Chile spanning from the approbation of the 1925 Constitution on 18 September 1925, under the government of Arturo Alessandri Palma, to the fall of the Popular Unity government headed by the President Salvador Allende on September 11, 1973. The period spans the same time as the "Development inwards" (Desarrollo hacia adentro) period in Chilean economic history.

A presidential system is a system of government where a head of government is also head of state and leads an executive branch that is separate from the legislative branch. The United States, for instance, have a presidential system. The executive is elected and often titled "president" and is not responsible to the legislature and cannot, in normal circumstances, dismiss it. The legislature may have the right, in extreme cases, to dismiss the executive, often through impeachment. However, such dismissals are seen as so rare as not to contradict a central tenet of presidentialism, that in normal circumstances using normal means the legislature cannot dismiss the executive.