Mount Ashio, Mountain summit in Ibaraki Prefecture, Japan.

Mount Ashio is a 627.5 m peak on the border of Ishioka and Sakuragawa in Ibaraki Prefecture, one of the northern peaks of the Tsukuba range, between Maruyama and Kinokoyama. Its summit holds the main hall of Ashio Shrine, with the worship hall just below. Trails lead up from Kozuke and Koya in Ishioka and from Shirai in Sakuragawa.

The mountain appears in the Hitachi no Kuni Fudoki as Ashio-san (葦穂山). According to tradition, Emperor Daigo prayed at its shrine and was cured of a leg ailment, whereupon he granted the shrine the plaque 'Japan's first Ashio Shrine' and the mountain took the name Ashio. Until the Meiji, Taishō and early Shōwa eras, pilgrims visited some 800 sacred sites on its slopes; these are now abandoned.

The summit holds the main hall of Ashio Shrine, with its worship hall just below; the shrine is known for healing foot ailments, so many straw sandals, shoes and prosthetic legs are left as offerings. The mountain was once a centre of mountain worship with 800 sacred sites, and pilgrims kept coming until the early Meiji, Taisho and Showa years. At the foot in Kozawa, Ishioka, stand the shrine's village sanctuary and Oigan-ji, its former administrative temple.

The mountain is accessible via several established trails with parking areas at the base and rest stations along the routes. Visitors should wear sturdy footwear and check weather conditions, especially during rainy seasons.

The ridge from Mount Ashio to Kinoko-yama holds several launch sites for hang gliders and paragliders, as sky sports are popular around the Tsukuba range. The mountain also lies on a Kanto Fureai no Michi hiking course.