Mount Ushiro (後山, Ushiro-yama) is a mountain on the border of Shisō, Hyōgo Prefecture, and Mimasaka, Okayama Prefecture, Japan.

It is the highest mountain in Okayama Prefecture and the third highest mountain in Hyōgo Prefecture, after Mount Hyōno and Mount Mimuro.

Mount Ushiro is a center of Shugendō in this region, and called Nishi-Omine, literally, West Omine.

According to a local narration in this area{fact}, this mountain was developed as a training area by En no Gyōja, the founder of Shugendō in the 7th century, for Shugensha, practitioners of Shigendō.

Mount Ushiro is one of the mountains which still have some areas which women are prohibited to enter so as to not to bother the training of Shugensha.