Ko Chang-seong (Korean: 고창성; Hanja: 高昌成; born December 21, 1984, in Seoul, South Korea) is a sidearm pitcher playing for the NC Dinos in the KBO League.

Ko played college baseball at Kyungsung University in Busan.

In the set-up role, Ko drew the attention of the league when he posted a 1.95 ERA and earned 16 holds in 2009.

He enjoyed another great season as a setup man in 2010, when he earned 22 holds which was runner-up in the KBO league.

[1] After the 2010 season, Ko was selected for the South Korean national baseball team to compete in the 2010 Asian Games where he won the gold medal.