Tadashi Ōtsuka

Tadashi Ohtsuka (大束忠司, Ōtsuka Tadashi, born April 30, 1978 in Nagasaki, Nagasaki) is a male badminton player from Japan.

Otsuka competed in badminton at the 2004 Summer Olympics in men's doubles with partner Keita Masuda. They had a bye in the first round, then were defeated in the round of 16 by Fu Haifeng and Cai Yun of China. He also competed in mixed doubles with partner Shizuka Yamamoto. They were defeated in the round of 32 by Robert Blair and Natalie Munt of Great Britain.

Ohtsuka played at the 2007 BWF World Championships in men's doubles with Keita Masuda, and were defeated in the third round by the eventual champions Markis Kido and Hendra Setiawan, of Indonesia, 22-20, 21-19.