Kosuke Hagino, Japanese swimmer
Kosuke Hagino (萩野公介, Hagino Kōsuke, born 15 August 1994) is a Japanese former competitive swimmer who specialized in the individual medley and 200 m freestyle.

He is a four-time Olympic medalist, most notably winning gold in the 400 m individual medley at the 2016 Summer Olympics.

Hagino holds the Asian Records in the 400 m individual medley (long course), the 100 m and 200 m individual medley (short course). With Team Japan, he holds the Asian Record for the 4×100 m freestyle relay (short course).

Hagino attends Toyo University, and is coached by Norimasa Hirai. He is one of the only two Asians to have been voted World Swimmer of the Year.