The BRP Rajah Humabon (PS-11) was a former destroyer escort of the United States Navy and a former frigate of the Philippine Navy. She was the last World War II-era destroyer escort/frigate active in her fleet, and one of the oldest active warships in the world, until 15 March 2018 when she was formally decommissioned after 75 years. She was one of three ex-USN Cannon-class destroyer escorts that served the Philippine Navy, the others being BRP Datu Sikatuna (PF-5/PS-77) and BRP Datu Kalantiaw (PS-76).

The Cannon class was a class of destroyer escorts built by the United States primarily for antisubmarine warfare and convoy escort service during World War II. The lead ship, USS Cannon, was commissioned on 26 September 1943 at Wilmington, Delaware. Of the 116 ships ordered, 44 were cancelled and six were commissioned directly into the Free French Forces. Destroyer escorts were regular companions escorting vulnerable cargo ships.