Ajisu (阿知須町 Ajisu-chō) was a town located in Yoshiki District, Yamaguchi, Japan.
On October 1, 2005 Ajisu, along with the town of Tokuji, from Saba District, and the towns of Aio and Ogōri, all from Yoshiki District, was merged into the expanded city of Yamaguchi.
As of 2003, the town had an estimated population of 8,926 and a density of 350.18 persons per km². The total area was 25.49 km².