Guillermo Irizarry-Rubio (April 12, 1916 – November 21, 2017) was a Puerto Rican politician who served as the Secretary of State of Puerto Rico. Appointed by Governor Roberto Sánchez Vilella, he served from 1966 to January 2, 1969, when he was responsible and led the first transition team under the Puerto Rican Constitution to the opposing political party. Prior to serving as Secretary of State, which includes the role of Lieutenant Governor of Puerto Rico, Irizarry served as head of Puerto Rico's Bureau of the Budget.