Yoshii (吉井町; Yoshii-chō) was a town located in Kitamatsuura District, Nagasaki, Japan.
On April 1, 2005 Yoshii, along with the town of Sechibaru, also from Kitamatsuura District, was merged into the expanded city of Sasebo.
As of 2003, the town had an estimated population of 6,092 and a density of 224.88 persons per km². The total area was 27.09 km².