Jeong Yoon-Oh (born Jeong Jae-hyun (정재현), February 14, 1997), known professionally as Jaehyun, is a South Korean singer-songwriter, actor and rapper. He is a member of the South Korean boy band NCT and its sub-units NCT 127 and NCT DOJAEJUNG. He made his solo debut on August 26, 2024, with the studio album J.

Apart from music, he has also hosted the radio show NCT Night Night from March 2017 to January 2019 and the television program Inkigayo from October 2019 to February 2021. He later debuted as an actor with a leading role in the college romance television series Dear. M (2022), and he made his feature film debut in the mystery thriller film You Will Die In 6 Hours (2024). As of 2024, Jaehyun is a global ambassador for the Italian luxury brand Prada; he is considered among the most impactful fashion ambassadors from South Korea.