Oh Jung-se (Korean: 오정세) is a South Korean actor. He is best known for his lead roles in the television series It's Okay to Not Be Okay (2020), Uncle (2021), Revenant (2023), Mr. Plankton (2024), and Good Boy (2025), as well as the film Swing Kids (2018) and Hi-Five (2025). He won Best Supporting Actor – Television at the Baeksang Arts Awards for two consecutive years in 2020 and 2021.