"Bengawan Solo" is a famous Indonesian song about the Solo River, which flows through central and eastern Java, Indonesia and is that island's longest. The song describes the legendary river in a poetic and nostalgic way, that it is surrounded by mountains, its sources are near the city of Surakarta, that it ends in the sea, and that the merchants use it.

Written in 1940 by Gesang Martohartono, (1 October 1917 – 20 May 2010) it is in the local kroncong style, a popular folk style with influences from Portuguese. The Japanese, who occupied the country during World War II, brought "Bengawan Solo" home with them to Japan after the war. There, and in the rest of Asia and later worldwide, the song became very famous.

The song's widespread popularity began soon after its composition. Locally it is strongly associated with the war occupation and the society of the time. In 1940 Gesang, then a young, destitute and untrained musician, composed "Bengawan Solo" on a bamboo flute and began to sing it at local functions and gatherings in his hometown of Surakarta. It soon became well-known and liked among the local Japanese community; the song then achieved national acclaim after it was broadcast to a wider audience by radio stations.

Its melodies appealed to the occupying Japanese soldiers and the non-Indonesian prisoners (mainly Dutch civilians) in the internment camps. "Bengawan Solo" was taken back to Japan by the returning soldiers, where it (with the lyrics translated to Japanese) gained great popularity after singers such as Toshi Matsuda released recorded versions of it which became best-sellers. The song has become almost synonymous with the perception of Indonesian music in Japan.

In 1991, a group of appreciative Japanese war veterans arranged for a statue of Martohartono to be erected in a park in Surakarta. Gesang himself was still resident in the city, now a nationally renowned figure.^[1]

Several artistes have recorded "Bengawan Solo," among whom are Waljinah, Toshi Matsuda, Anneke Grönloh, Rebecca Pan, Frances Yip, P.Ramlee and Saloma.

"Bengawan Solo" is a popular name given to restaurants and businesses, in reminiscence of the song.