Keiichiro Matsui is a Japanese badminton player. He is a former member of the Japanese national team. Previously affiliated with the Hitachi team, Matsui officially joined the AC Nagano Parceiro Badminton Club in March 2026. Born in Ishikawa, he graduated from the Tomioka senior high school, and later educated at the Nippon Sport Science University. He was part of the national junior team that won the gold medal at the 2012 Asian Junior Championships, and the silver medal at the 2012 World Junior Championships.