Musa Otsuka Kofun, Ancient burial mound in Kita Ward, Japan.

Musa Otsuka Kofun is a circular tumulus on the southern slope of the Takakurayama massif on the east bank of the Asahi River in Kita-ku, Okayama. Its mound is now 30 metres across and 8.5 metres high, though it is thought to have measured over 40 metres wide and 10 metres high before its edges were cut away. A south-facing two-sleeve corridor stone chamber runs 18 metres, built of huge granite blocks, with a hollowed house-shaped sarcophagus of Namigata shell tuff from Ibara inside.

Built around the end of the 6th century, the mound is the latest of Okayama Prefecture's three great megalithic tombs, following Kōmori-zuka and Yada Ōtsuka. It was reported by Kiyono Kenji in 1905 and by Umehara Sueji in 1924, and was designated a National Historic Site on 28 February 1930. No excavation has ever been carried out; the mound was surveyed in 1968 by the Okayama City Board of Education and Okayama University.

The name Musa Ōtsuka combines the neighborhood name Musa with ōtsuka, meaning "large mound." The tumulus stands alone, with no ancient temple ruins nearby, and is grouped with the Kōmori-zuka and Yada Ōtsuka tumuli as one of Okayama Prefecture's three great megalithic tombs. Its position near the old San'yōdō crossing of the Asahi River and the Takakurayama ritual site is noted by researchers.

The mound stands on the southern foot of the Takakurayama massif on the east bank of the Asahi River in Musa, Kita-ku, Okayama; the old San'yōdō road and the Musa river crossing ran nearby. The burial chamber opens to the south, and the mound's surroundings have been flattened, so the present diameter is about 30 metres and the height 8.5 metres. No excavation has been carried out, so the interior is known only from surveys.

No excavation has ever been carried out at Musa Ōtsuka Kofun, so the grave goods remain unknown; the hole cut into the side of the house-shaped sarcophagus is the work of looters in antiquity. Together with the Kōmori-zuka and Yada Ōtsuka tumuli it forms the three great megalithic tombs of Okayama Prefecture.