Leonardo A. Quisumbing (born November 6, 1939) was an Associate Justice of the Supreme Court of the Philippines. He was appointed by President Fidel Ramos in 1998 and retired as the most senior Associate Justice of the Court on his 70th birthday in 2009.

Hailing from Masbate, Masbate, Quisumbing graduated Valedictorian of the Masbate High School in 1959. He was a prominent campus figure as an undergraduate student at the Manuel L. Quezon University, where he edited The Quezonian, graduated magna cum laude, A.B. Journalism, and as a law student at the University of the Philippines. While at U.P., he was the President of the University Student Council, the President of the Student Councils Association of the Philippines, and an editor of the Philippine Collegian. He earned his law degree from the U.P. College of Law in 1966. He placed 12th in the 1966 Bar Examinations and he pursued post-graduate studies at Cornell University, New York, obtaining a Master of Laws degree and he was a NEC-AID Scholarship grantee. Quisumbing was a member of the National Debating Team to Australia that won the Wilmot Cup. On a Fulbright Youth Leader grant, he visited Harvard, Columbia, Georgetown, and other universities. He was also a delegate to the 11th International Student Conference in 1965 at Christchurch, New Zealand.