Mount Miwa (三輪山, Miwa-yama) or Mount Mimoro (三諸山, Mimoro-yama) is a mountain located in the city of Sakurai, Nara Prefecture, Japan. It has been an important religious and historical mountain in Japan, especially during its early history, and serves as a holy site in Shinto. The entire mountain is considered sacred, and is home to one of the earliest Shinto shrines, Ōmiwa Shrine. Several burial mounds from the Kofun period can be found around the mountain.

The kami (spirit) generally associated with Mount Miwa is Ōmononushi (大物主) (Ōmono-nushi-no-kami), a rain kami. However, the Nihon Shoki notes that there was a degree of uncertainly when it came to naming the principal kami of Mount Miwa, but he is often linked to Ōkuninushi.

Mount Miwa was first described in the Kojiki as Mount Mimoro (三諸山). Both names were in common use until the reign of Emperor Yūryaku, after which Miwa was preferred. Mimoro has been held to mean something like "august, beautiful" (mi) and "room", or "hall" (moro corruption of muro). The current kanji (三) (mi) and (輪) (wa) are purely phonetic. It has also been written (三和), another a phonetic spelling with the same pronunciation.

Religious worship surrounding Mount Miwa has been deemed the oldest and more primitive of its kind in Japan, dating to pre-history. The very mountain itself is designated sacrosanct, and today's Ōmiwa Shrine still considers the mountain to be its shintai, or kami-body. The kami residing on Mount Miwa was judged the most powerful by the Fujiwara clan, and consequently palaces and roads were built in the vicinity. The saiō Princess Uji also worshipped here as opposed to Mie Prefecture.

The Nihon Shoki, Book V, (Chronicle of Emperor Sujin, 10th emperor) records that when the country was crippled by pestilence and subsequent mayhem, the emperor consulted the gods. The god Ōmononushi (whom some sources to the chronicle identify with the Mount Miwa deity) spoke through the mouth of an elder princess of the imperial house named Yamato-to-to-hi-momoso-hime (daughter of 7th emperor Emperor Kōrei and Sujin's aunt) and revealed himself to be the deity residing in the borders of Yamato on Mount Miwa, and promised to bring end to chaos if he were properly worshipped. The emperor propitiated to the god but the effects were not immediate. Later, the same god appeared in a dream to and instructed him to seek out a man named Ōtataneko [ja] (太田田根子), said to be the child of the god, and to install him as head priest of his cult. Subsequently, normal order was restored and crops no longer failed. Ōtataneko [ja] would become the ancestor of the Miwa clan.

The Nihon shoki records that the first priest of the shrine, Ōtataneko [ja] declares himself the son born between the god and Ikutama yori-hime (or Ikudama-yori-bime). However, in the Kojiki, Ōtataneko [ja] identifies himself as the great-grandson (Ōtataneko [ja] and Iku-tama-yori-bime begat Kushi-mikata, who begat Iikatasumi, who begat Takemikazuchi who begat the priest Ōtataneko [ja]).

Kojiki tells how it became known Ikutama yori-hime was divinely conceived. The beautiful girl was found to be pregnant, and claimed a handsome being had come to her at night. Her parents, in order to discover the identity of the man, instructed her to sprinkle red earth by her bedside, and thread a hemp cord (or skein) with a needle through the hem of his garment. In the morning, the hemp went through the hole of the door-hook so that only "three loops" (miwa) were left. They trailed the remaining hemp thread to the shrine in the mountain, and that was how they discovered the visitation was divine.

The Kojiki also records another divine birth from an earlier period (under Emperor Jimmu). It tells how a maiden named Seya-datara was squatting in the toilet when the god transformed into the shape of a red-painted arrow and poked her in her privates. In astonishment, she picked up the arrow and placed it by the floor, whereby it transformed into a fine youth, who wound up marrying her. The girl child then born was named Hoto-tatara-i-susuki-hime (or Hotota-tara-i-susugi-hime), hoto being an old word for a woman's private parts.