Gu Sung-yun (Korean: 구성윤, born 27 June 1994) is a South Korean professional footballer who plays as a goalkeeper for Kyoto Sanga, on loan from Consadole Sapporo.

[4] On 25 September 2022, it was announced that Gu would return to Hokkaido Consadole Sapporo for the 2023 J1 League season.

On 25 July 2023, Consadole loaned Gu Sung-yun to Kyoto Sanga until the end of the season.

Gu was part of the senior South Korea squad for the 2015 EAFF East Asian Cup.

This biographical article related to a South Korean association football goalkeeper is a stub.