The Yamaguchi Line (山口線, Yamaguchi-sen) is a railway line in western Japan operated by West Japan Railway Company (JR West).

The line connects Shin-Yamaguchi Station in Yamaguchi, Yamaguchi and Masuda Station in Masuda, Shimane.

The Ogori (now Shin-Yamaguchi) - Yamaguchi section opened in 1913, and the line was progressively extended north, reaching Masuda in 1923.

The Super Oki limited express connects Shin-Yamaguchi Station with Yonago Station and Tottori Station on the Sanin Main Line via the Yamaguchi Line.

The line is also famous for the operation of the rapid SL Yamaguchi steam train.