O Yeong-su (Korean: 오영수; born O Se-kang, October 19, 1944) is a South Korean actor. In 2021, he portrayed Oh Il-nam in the Netflix survival drama Squid Game, which gave rise to his worldwide popularity and won him a Golden Globe Award for Best Supporting Actor in a Series, Miniseries or Television Film, as well as a nomination for the Primetime Emmy Award for Outstanding Supporting Actor in a Drama Series.