Kwanthai Sithmorseng (Thai: ขวัญไทย ศิษย์หมอเส็ง) is a professional boxer from Thailand. He fights in the strawweight division and is the reigning WBA Minimumweight World champion. He captured the title on November 5, 2010 by defeating Pigmy Kokietgym.
Early life he was an orphan born without knowing who the parents, he beginning boxing from Muay Thai.
He lost the WBA Minimumweight title on April 19, 2011 to Muhammad Rachman by KO.