Juan Marquez Sumulong Sr. (born Juan Sumulong y Marquez; December 27, 1875 – January 9, 1942) was a Filipino former revolutionary, journalist, lawyer, educator and politician from the province of Rizal. He was the president of the opposition party which ran against Manuel L. Quezon's Nacionalista Party in the 1941 presidential election of the Philippine Commonwealth. He is also the maternal great-grandfather of former President Benigno Aquino III.
