Nagai Stadium, officially known as Yanmar Stadium Nagai, is a major sports venue located in Osaka, Japan. Opened in 1964 and renovated several times since, the stadium is part of the Nagai Park complex, which includes additional sports facilities and training areas.

With a seating capacity of around 47,000, Nagai Stadium features a high-quality track and has been a key site for both domestic and international athletics competitions including the 2007 World Athletics Championships.