Santiago Iglesias Pantín (February 22, 1872 – December 5, 1939), was a Spanish-born Puerto Rican socialist and trade union activist.

After losing a race in 1908 against Tulio Larrínaga for Puerto Rico's non-voting delegate seat in the United States Congress, Iglesias was elected as a Coalitionist Resident Commissioner on November 8, 1932, and was reelected in 1936 for the term ending January 3, 1941.

Married to Justa Pastora Bocanegra in 1902,[4] he had eight daughters, named America, Libertad, Igualdad, Justicia, Paz, Luz, Fraternidad and Victoria,[5][6] and three sons, including the late U.S. Navy career military officer and fighter airplane pilot Captain Edward Iglesias, elected in 2004 into The Early and Pioneer Naval Aviators, better known as the Golden Eagles; the late Manuel Francisco Iglesias, distinguished Air Force Captain and Lead Crew Radar Office of the B-29s during World War 2 both awarded Distinguished Flying Cross medals; and Angel Santiago.

Iglesias died in office in Washington, D.C., on December 5, 1939, and his body was returned home to Puerto Rico, where it lay in state at the Capitol.

[4] Iglesias's body was interred in a tomb at Santa Maria Magdalena de Pazzis Cemetery in San Juan, Puerto Rico.