Tomonari Ono (born February 7, 1974) is a Japanese former sprinter who specialized in the 400 and 800 meters.

He won a bronze medal in the 4x400 m relay at the 1995 World Indoor Championships in Barcelona, along with Hiroyuki Hayashi, Seiji Inagaki, and Masayoshi Kan.

He also won a bronze medal in the 1992 World Junior Championships in the 4x400 m relay.

Ono holds the Japanese under 20 record in the indoor 800 meters, with a time of 1:49.09.

This biographical article relating to Japanese athletics is a stub.