Callao Cave (IPA: [ˈkalaʊ]) is one of 300 limestone caves located in the Barangays of Magdalo and Quibal in the municipality of Peñablanca, about 24 km (15 mi) northeast of Tuguegarao City, the capital of Cagayan province within the Peñablanca Protected Landscape and Seascape in the western foothills of the Northern Sierra Madre Mountains on Luzon island in the Philippines. The town Peñablanca's (Spanish: white rocks) name refers to the predominance of white limestone rock formations in the area. First excavated in 1980 by Maharlika Cuevas, the seven-chamber show cave is the best known natural tourist attraction of the Cagayan province and in February 2020 has officially been recognized as an important cultural property of the Philippines.

These fossils of archaic humans, that lived during the Late Pleistocene were first discovered in the cave and documented in 2007 by a team led by Armand Salvador Mijares from the University of the Philippines Diliman and eventually confirmed in 2019 to belong to a previously unknown and now extinct human sub-species - Callao Man or Homo luzonensis.

Callao Cave was visited by American Governor-General Theodore Roosevelt Jr. in 1932 who, during his term, created the National Park system of the country with the passing of Act No. 3195 in 1932. Callao Cave was one of the earliest national parks in the country when it was established on July 16, 1935, by Proclamation no. 827. The Callao Cave National Park encompasses an area of 192 hectares (470 acres) of land. With the passing of the NIPAS Act of 1992 that revamped the protected areas of the country, the Callao National Park was reclassified but enlarged by Proclamation no. 416 on June 29, 1994. The protected area was reestablished as the Peñablanca Protected Landscape.

In 2003 upon the recommendation of the Department of Environment and Natural Resources (DENR), the protected area was further enlarged to include certain parcels of land in the public domain. Proclamation 416 no. was amended by Proclamation no. 484, signed by President Arroyo on October 6, 2003. The law enlarged the park to 118,781.58 hectares (293,515.7 acres) and renamed it the Peñablanca Protected Landscape and Seascape (PPLS).

The protected area is particularly described as bounded on the North and East of Public Forest under FR-1011 per Proclamation No. 584 dated July 8, 1940; on the South by Callao Reforestation Project and on the West by Block I, Alienable and Disposable of Cagayan Project No. 13-C, Certified on February 27, 1923.

More than 300 caves dot the protected area, 75 of which have been documented by the National Museum since 1977. The Callao Cave and the nearby, but more challenging, Sierra Cave are easily accessible by automobile.

The Callao Cave is the premier attraction in the Peñablanca Protected Landscape and Seascape. It is the most accessible of all the caves, its entrance is reached by climbing 184 concrete steps. The Callao Cave system is composed of seven chambers, each with natural crevices above that let streams of light into the cave, serving as illumination for the otherwise dark areas of the place. Previously, there were reported to be nine caves in the system, but an earthquake in the 1980s cut off the last two chambers.

The first chamber of the show cave is the largest room with a width of about 50 m (160 ft) and a height of 36 m (118 ft). The cathedral-like room has been turned into a chapel by the local people. A rock formation serves as the altar of the chapel lit by a stream of light coming from a rooftop opening. The conditions inside the caves have caused the formation of stalactites and stalagmites, more so in the deeper chambers. Several spectacular speleothems or formations are found inside the cave like flowstones, glittering dripstones, cave curtains, crystal helictites, columns, etc.