The Gabai River (Malay: Sungai Gabai), a minor river in the Langat River basin, flows from the 1,462-metre-high (4,797 ft) Big Ghost Mountain (Malay: Gunung Besar Hantu) in the state of Negeri Sembilan, Malaysia into the Dipterocarp forest reserve of the Hulu Langat district in the adjacent state of Selangor.
In Hulu Langat, the river descends in a set of waterfalls known as the Gabai Falls (Malay: Air Terjun Sungai Gabai), a popular attraction for the locals, but relatively unknown with tourists. A cemented path leads from the parking to the lower falls. Along the path several shelters have been built. The upper falls can be reached by trails.