Ryuichi Funai (船井龍一, Funai Ryuichi, born 13 August 1985) is a Japanese professional boxer.

He is the current WBO Asia Pacific Super Flyweight Champion and held the Japanese Super Flyweight title.

Funai is highly ranked in the Super Flyweight Division at #11 and in 2018-2019 ranked by the IBF at #1 spot.

On 14 June 2018, Funai fought former world title contender Warlito Parrenas of the Philippines for the WBO Asia Pacific super-flyweight title, and won it by 8th-round knockout.

Funai faced Jerwin Ancajas for the IBF super-flyweight title on 5 May 2019, losing by a 7th round stoppage due to ring doctor's advice.