Goichi Suda (須田剛一, Suda Gōichi, born January 2, 1968), known by his alias Suda51, is a Japanese video game director, designer, and writer. Affiliated with Human Entertainment from 1994 to 1998, he founded Grasshopper Manufacture in 1998 with a number of other Human Entertainment staff to produce their own titles. His best-known work has come from Grasshopper Manufacture, including The Silver Case (1999), Killer7 (2005), the No More Heroes series, and Lollipop Chainsaw (2012).

Suda is from Nagano Prefecture, moving to Tokyo at the age of 18 and eventually being hired by Human Entertainment after having a number of other jobs including as an undertaker. His first projects were in the Fire Pro Wrestling and Twilight Syndrome series. At Grasshopper Manufacture, he worked on their debut title The Silver Case as writer and director. The Silver Case helped establish both Suda and his company in Japan, but Suda and Grasshopper gained international attention with the release of Killer7, Suda's first title to be released outside Japan. He has contributed to most of the company's projects, taking on a more managerial role following No More Heroes in 2007.

Suda's work is characterized by a focus on themes of crime, and the clash of people with different ideals. While his early works adopted a serious tone, his later projects incorporated elements of humor. Sexual elements have also made appearances in his work to the point where he became worried they would become too heavily associated with him. Aspects of his work have been influenced by film and literature, with one of his favorite authors being Franz Kafka. He frequently incorporates references to pop culture in his games.