The Kesennuma Line (気仙沼線, Kesennuma-sen) is a local railway and bus rapid transit line in Japan, operated by the East Japan Railway Company (JR East). It connects Maeyachi Station in the city of Ishinomaki, Miyagi to Kesennuma Station in the city of Kesennuma, Miyagi. The route links the northeastern coast of Miyagi Prefecture with the Ishinomaki Line (and the Tohoku Main Line a few stops farther) available for transfer in the south, and the Ōfunato Line in the north.

Originally a railway from end to end, the line was severely damaged by the 2011 Tōhoku earthquake and tsunami, with tracks, stations, and railway bridges between Minami-Kesennuma Station and Rikuzen-Togura Station sustaining major damage. Destroyed stations included Minami-Kesennuma (except for the platform) and Shizugawa Station, as well as various others. As a result of the catastrophic damage to the line and prohibitive costs of restoration as a railway, JR East officially proposed the line's conversion into a dedicated bus rapid transit route on 27 December 2011. At present only the Maeyachi to Yanaizu section is operated as a railway, with services on the remainder of the route provided by buses. The buses have been Level 2 self-driving since December 2022.

Although the Kesennuma Line's south end is Maeyachi, its operational south end should be considered Kogota Station in Misato, as the majority of Kesennuma Line trains either have Kogota as their south terminus or go through it on the way to Sendai. Trains going this far also stop at Kami-Wakuya (local only) and Wakuya Stations in Wakuya, Miyagi on the Ishinomaki Line.

Greyed-out stations have been closed since the 2011 Tōhoku earthquake and tsunami, and operate only as bus stops for the JR East BRT route.