Ryan S. Jhun () is a South Korean songwriter and record producer. Jhun is known for his work with various K-pop soloists and idol groups, getting his start through acts from SM Entertainment such as Shinee, Super Junior, f(x), Taeyeon, Exo, NCT, and TVXQ. He has since produced for several artists from other labels like IU, Loona, Lee Hyo-ri, U-KISS, Girl's Day, Twice, NMIXX, Oh My Girl, Monsta X, Ive, BAE173, and Cravity, as well as songs for audition programs Produce 101 and My Teenage Girl.
He founded and became chief executive officer of music production and publishing company Marcan Entertainment. He is also the CEO of Ateam Entertainment, where he produced for the label's groups VAV and BugAboo.
Jhun was born in South Korea on February 28, 1979. He moved to New York at ten years old, where he began being interested in music. He auditioned for SM Entertainment for what would eventually become boy band Shinhwa, however he was discouraged by his parents. He later traveled back to South Korea to submit his demos, with only SM accepting his music. His first released song was "Chitty Chitty Bang Bang" for Lee Hyori's album H-Logic (2010), while his first "hands-on" song was "Lucifer" for Shinee for their album of the same name.
Jhun is also CEO of Ateam Entertainment, having joined in 2017 to produce for their boy group VAV. In 2021, he debuted his first girl group, BugAboo, under Ateam. Jhun was awarded Best Songwriter at the 2023 Melon Music Awards.
Jhun is known for his "crossover" musical style, with his production incorporating elements from world music. He also co-founded songwriting and production teams Marcan Entertainment and Musikade, and regularly collaborates with Denzil Remedios, LDN Noise, and Dem Jointz.
All song credits are adapted from the Korea Music Copyright Association's database unless stated otherwise.