| Mount Myōkō | |
| Elevation M: | 2454 |
| Elevation Ref: | [1] |
| Prominence: | 439m |
| Prominence Ref: | [2] |
| Listing: | 100 Famous Japanese Mountains |
| Language: | Japanese |
| Pronunciation: | pronounced as /ja/ |
| Location: | Chūbu region, Honshu, Japan |
| Range: | Kubiki Mountains |
| Coordinates: | 36.8881°N 138.1166°W |
| Map: | Japan Niigata Prefecture |
| Type: | Stratovolcano |
| Last Eruption: | 750 BCE |
| Easiest Route: | Hike |
is an active stratovolcano in Honshu, Japan. It is situated at the southwest of Myōkō city, Niigata Prefecture, and a part of Jōshin'etsu-kōgen National Park. Mount Myōkō is listed as one of 100 Famous Japanese Mountains, and together with, it is well known as the "famous mountain" of Niigata Prefecture.
is another name given to this mountain. Being close to the border with Nagano Prefecture, it is linked to those on the Nagano side as one of the . The mountain was originally named but was later changed to . This can be also written as 妙高山, in order to make use of two "lucky" characters.
Mount Myōkō was formed beginning about 300,000 years ago, in a series of eruptions producing a broad spectrum of lava types including basalt, andesite, and dacite. Its maximum height is estimated to have been between 2800m (9,200feet) and 2900m (9,500feet), but it presently reaches only 2454m (8,051feet). Around 19,000 years ago, the top was blown off in a major eruption, forming a 30NaN0 wide caldera. About 6,000 years ago, the central crater developed and assumed its present shape. A lava dome forms the volcano's present summit. The most recent eruptions about 4,300 years ago produced pyroclastic flows down the eastern flanks. Present activity is solfataric from fumaroles near the lava dome where sulfur was once mined.
There are onsen and ski resorts at the foot of the mountain, including Akakura, Suginohara and Ikenotaira.
The heavy cruiser Myōkō of the Imperial Japanese Navy and an Aegis destroyer of the Japan Maritime Self-Defense Force are named after this mountain. The JR East train service Myōkō is also named after the mountain.
The mountain appears invariably in school songs of elementary and middle schools in the Jōetsu Region.
In 1990 the Nippon Jamboree, a camping festival, was held on the during which the participants climbed the mountain.