Yanai, Yamaguchi

 is a city located in Yamaguchi Prefecture, Japan. The city was founded on March 31, 1954.
The interchange and the expressway is located in the east. Yanai is bounded by Hikari.
As of October 1, 2016, the city has an estimated population of 32,490 and a population density of 230 persons per km². The total area is 139.90 km².
On February 21, 2005, the town of Ōbatake (from Kuga District) was merged into Yanai.