During a change of ends Sunday in the doubles final, Bodin Issara lunged at Maneepong Jongjit, chasing him onto a neighboring court before punching him several times.
Issara was dragged away and held down by coaches and tournament staff, while his partner, Pakkawat Vilailak, escorted a shirtless Jongjit off the court.
Issara, who needed two stitches, says Jongjit hit him with a badminton racket. The pair had already received a warning from the referee following a verbal exchange.
Jongit and partner Nipitphon Puangpuapech, also from Thailand, were awarded the victory after Issara was shown a black card.
"The events surrounding the conclusion of this match will be thoroughly investigated by the BWF," the federation said Monday in a statement. "The world governing body has procedures in place to deal with such situations and this matter will be referred to the Disciplinary Committee."
Jongjit and Issara were among the top-ranked badminton pairings and reached the quarterfinals at the 2012 Olympics. They split in January, when Issara retired to take care of his ailing mother, but was soon competing again with another partner.