Tengu (天狗, "heavenly dog") are a type of legendary creature found in Japanese folk religion and are also considered a type of Shinto god (kami) or yōkai (supernatural beings). Although they take their name from a dog-like Chinese demon (Tiangou), the tengu were originally thought to take the forms of birds of prey, and they are traditionally depicted with both human and avian characteristics. The earliest tengu were pictured with beaks (called Karasu Tengu (烏天狗), lit. "crow tengu"), but this feature has often been humanized as an unnaturally long nose (called Hanataka Tengu (鼻高天狗), lit. "high-nosed tengu", or Ootengu (大天狗), lit. "greater tengu"), which today is widely considered the tengu's defining characteristic in the popular imagination.

Buddhism long held that the tengu were disruptive demons and harbingers of war. Their image gradually softened, however, into one of protective, if still dangerous, spirits of the mountains and forests. Tengu are associated with the ascetic practice known as Shugendō, and they are usually depicted in the distinctive garb of its followers, the yamabushi.