Francisco Dueñas Díaz (3 December 1810 – 4 March 1884) was a Salvadoran politician and member of the Conservative Party who served as President of El Salvador on four different occasions between 1851 and 1871.

He served in this position until February 1840 when he resigned in protest of Morazán's invasion of Guatemala as a part of the Second Central American Civil War.

Dueñas fled El Salvador to Guatemala when Barrios overthrew President Miguel Santín del Castillo.

[5] In 1863, Dueñas and other exiled conservatives supported Carrera's invasion of El Salvador and sought to overthrow Barrios.

On 29 August 1865, the legislature amended article 33 of the constitution of El Salvador to allow Dueñas to run for re-election.

Dueñas was overthrown by Field Marshal Santiago González Portillo on 15 April 1871 and seized the presidency.

[5] On 12 February 1866, Dueñas married Teresa Dárdano in a ceremony presided over by Tomás Pineda y Zaldaña, the bishop of San Salvador.