Benjamín Lacayo Sacasa (27 June 1893 – 4 April 1959) was the President of Nicaragua from 27 May to 15 August 1947.
He was a relative of Silvestre Selva, 17th President of Nicaragua, Roberto Sacasa, 44th and 46th President, and his son Juan Bautista Sacasa, 63rd President, as well as a cousin of Roberto Martínez Lacayo, 74th and 75th President of Nicaragua from 1 May 1972 to 1 March 1973 and from 1 March 1973 to 1 December 1974, and Arnoldo Alemán, 81st President of Nicaragua.
On 26 May 1947, he was installed with the help of former president Anastasio Somoza García, the commander of the army, who had become dissatisfied with his recently elected successor, Leonardo Argüello. Lacayo served as president for three months.