The Petralona Cave (Greek: Σπήλαιο Πετραλώνων) a karst formation, is located at 300 m (984 ft) above sea-level on the western foot of Mount Katsika, about 1 km (0.62 mi) east of the village of Petralona, about 35 km (22 mi) south-east of Thessaloniki city on the Chalkidiki peninsula, Greece. The site came to public attention when in 1960 a fossilized archaic human skull was found. The cave had been discovered accidentally only a year earlier (1959) after erosion had left clefts in the rock. "Bejeweled" with impressive stalactite and stalagmite formations and holding an abundance of fossils, the cave soon attracted geologists and paleontologists. After decades' excavations the cave is open to the public and scientific work is documented and presented in an adjacent archaeological museum.

The cave's most prominent fossil specimen has since been known among paleoanthropologists as the "Petralona Skull".

The onsite museum displays a selection of the objects that have been found in the cave.

In 2011, the cave and museum of Petralona came under the direction of the Greek Archaeological Service, a governmental agency. Since February 2024, Petralona Cave has reopened to the public after undergoing renovations to its infrastructure, while within the spring of 2024, the renovated Museum of Petralona Cave is expected to open.^{[needs update]}

The cave was discovered accidentally in 1959 by Fillipos Chatzaridis, a local shepherd who was looking for a spring. In his effort to find a water source he found a small cleft on the slopes of Mount Katsika. Two men were lowered down and later described a large number of chambers and corridors, totaling 8 to 10 meters high with rich and beautiful formations of speleothems (stalactites and stalagmites).

The cave developed during the Mesozoic (Jurassic) limestone, its sediments are divided into several stratigraphic levels. "The rock formations resemble giant cactus, pink pearls, sturdy columns or delicate curtains, and in several places water ponds are fed by stalactite material. Covering an area of 10,400 m² (112,000 sq ft), the length of the corridors is about 2,000 m (6,562 ft) and the temperature throughout the year remains stable at 17 °C (± 1 °C)."

The first research of 1959 was undertaken by the Greek speleologist Ioannis Petrocheilos. He found numerous bones of animals, many of them covered with cave coral. From 1968 onward, excavations were carried out by the anthropologist Aris Poulianos. Poulianos complained that excavations on the site were delayed and/or had to be discontinued several times. The first instance was in 1968 and subsequent years due to the Greek coup d'état. Then again in 1983, when the Ministry of Culture declined to re-issue the excavation concession. However, in 1997, after 15 years of trials, the Anthropological Association of Greece was justified by the Supreme Court and ordered to continue its works in the cave. Poulianos repeatedly accused the Greek government of conspiring to suppress his discoveries, as evidenced by the revocation of excavation rights again in 2011.

The excavation research in the cave continues today by the relevant authority of the Hellenic Ministry of Culture, the Ephorate of Palaeoanthropology–Speleology, utilising modern methods and detailed documentation, with the aim of better understanding the history of the cave and its use by animals and humans.