Ryo Tateishi (?? ?, Tateishi Ryo, born 12 June 1989 in Kanagawa) is a Japanese swimmer.
At the 2012 Summer Olympics, he competed in the Men's 100 metre breaststroke, finishing in 7th place in the first semifinal, failing to reach the final.
Tateishi subsequently won a bronze medal in the 200 metre breaststroke.