Mount Yoko (横岳, Yoko-dake) also known as Mount Kita Yoko, is an active lava dome located in the Northern Yatsugatake Volcanic Group of the Yatsugatake Mountains, Honshū, Japan.

The mountain is famous for its hard rime snow monsters, called juhyo (樹氷) in Japanese.

The Kitayatsugatake Ropeway, which is open year-round, begins from 1,771 m (5,810 ft) above sea level in Chino, Nagano, to a height of about 2,237 m (7,339 ft) to Tsuboniwa Nature Park (坪庭自然園, Tsuboniwa shizen en), a natural garden of igneous rock and pines which originated from a volcanic eruption.

The mountain trail between Tsuboniwa and the summit is gentle and well-maintained, making it an easy route for beginners, even in winter.

In addition, although there are many climbers between the inner garden and the summit, there are very few people north of it, and it is not uncommon for tracks to disappear, especially in the winter.