Matsuokayama Kofun, Ancient burial mound in Kashiwara, Japan.

Matsuokayama Kofun is a keyhole-shaped burial mound in the Kokubu-ichiba neighborhood of Kashiwara, Osaka, on the highest point of the Matsuoka hills within the grounds of Kokubu Shrine. It measures about 130 meters long, with a 72-meter-diameter circular rear mound and a 32-meter-wide rectangular front mound, built in three or four tiers and two tiers respectively. The mound was faced with thin stone slabs and rows of cylindrical haniwa, and a stone sarcophagus now lies exposed at the top of the rear mound.

Built around the end of the 4th century, the mound was designated a National Historic Site in 1922, though only the rear circular portion is protected. Excavations in 1955 and 1984–1986 uncovered jadeite magatama, glass beads, bronze mirror fragments and iron weapons; most finds are kept at Kyoto University. A 1877 dig by Atsushi Saisho reportedly yielded mirrors and beads, now lost.

The mound lies within the grounds of Kokubu Shrine, and its alternative name, Miyama, derives from 'miya-yama' (shrine mountain). The name Matsuokayama replaced the older Matsuokayama spelling after the site was proposed as the find spot of the Funashi no Ōgo epitaph, though the burial mound predates that figure. Visitors can see the exposed stone coffin at the top of the rear circular mound.

The mound stands on the hilltop within the grounds of Kokubu Jinja, about 15 minutes on foot from Kawachi-Kokubu Station on the Kintetsu Osaka Line. The sarcophagus is exposed at the top of the rear circular mound, and the covering earth has eroded, so the scattered stone slabs and standing stones lie in the open. Excavated haniwa and pottery are kept at the Kashiwara City Historical Museum.

The sarcophagus is a six-stone combination: one lid and one base of biotite granite, four side stones of garnet-hornblende andesite or tuff probably from Kagawa Prefecture, two with rope-hanging protrusions. The base stone's surface is carved to fit the body. Two perforated standing stones flank it, 2.3 m and 1.8 m tall, of unknown purpose.