Supachai Koysub (born 15 July 1977)[1][2][3] is an athlete and Paralympian from Thailand competing mainly in category T54 sprint events.

He competed in the 2000 Summer Paralympics in Sydney, Australia.

He also competed at the 2004 Summer Paralympics in Athens, Greece.

He also competed at the 2008 Summer Paralympics in Beijing, China.

There he won a silver medal in the men's 4 × 100 metre relay – T53–54 event, a silver medal in the men's 4 × 400 metre relay – T53–54 event, a bronze medal in the men's 100 metres – T54 event, went out in the first round of the men's 200 metres – T54 event and finished sixth in the men's 400 metres – T54 event