Francisco Dueñas Díaz (3 December 1810 – 4 March 1884) was a Salvadorean politician and member of the Conservative Party who served as President of El Salvador from:
3 May 1851 – 30 January 1852 in acting capacity
1 February 1852 – 1 February 1854
1–12 February 1856 in acting capacity
26 October 1863 – 15 April 1871.He was "an ardent defender of the clerical interests.
Dueñas at one time had taken the vows as a Dominican, but when the convents were closed in 1829, he left the cloister and secured a papal dispensation." Under his leadership, "the clerical party was in the ascendancy and El Salvador experienced a far-reaching Conservative reaction."