The 115 series (115系, 115-kei) is a DC electric multiple unit (EMU) train type developed by Japanese National Railways (JNR) and now operated by West Japan Railway Company (JR-West), and the Shinano Railway.

JR East operated their last 115 series train on 11 March 2022. 115 series trains were previously used on the Shōnan-Shinjuku Line, Takasaki Line, Utsunomiya Line, Chuo Main Line(East Line), Shinonoi Line, Oito Line, Agatsuma Line, Ryomo Line, Joetsu Line, Shinetsu Main Line, Yahiko Line, and the Echigo Line.

Currently used on the Hakubi Line, Maizuru Line, Sagano Line, Sanin Main Line and the Sanyō Main Line

Formerly used on the Minobu Line, Gotemba Line and the Tōkaidō Main Line. Sets owned by JR East currently operate on the JR Central Iida Line and Chūō Main Line (West Line).

Currently used on the Shinano Railway Line. Start of retirement in July 2020 with the debut of the new SR1 series on 4 July 2020.

This is a cold-weather and mountainous line version of the earlier 113 series. The first examples were introduced from 1963 on the Takasaki Line out of Ueno.

Air-conditioned version introduced from 1973.

Introduced from 1978 with increased seat pitch and improved cold-weather performance.