Kim Yoon-jin (김윤진, born November 7, 1973 in Seoul, South Korea) is a South Korean actress.

At the age of 10, Kim immigrated to the United States with her family. As a shy teenaged girl in Staten Island, New York still getting accustomed to life in the U.S., she joined the middle school drama club in the 7th grade and found herself on the stage of the musical My Fair Lady. "I was cast as only an extra, but that day, I stood on the stage and sang loudly in my own voice..." she recalled. "When singing and acting on stage, I didn't feel the least bit awkward. I felt so at home under the lights... Something about being on stage just felt right."

Pursuing her passion, Kim moved to New York City, where she attended and her earned her diploma at the New York High School of Performing Arts. From there, she studied drama at the London Academy of Performing Arts and later earned her acting degree at Boston University.

After graduation, Kim devoted her full time to acting. She garnered several minor parts on MTV, in soap opera-style dramas on ABC, and on the Broadway stage. In 1996, a Korean TV show filming in Manhattan called and persuaded her to return to her homeland, to appear in the Korean TV drama A Gorgeous Vacation. This was followed by two other roles in Foreboding and the miniseries Wedding Dress. Then in 1997, based on the popularity she gained with her role in Wedding Dress, she was offered and accepted a script for her debut film. "Even then, I had no idea I would live in Korea," Kim said, "I thought I would finish the film and go back to the United States."

Surprisingly, that film was Shiri (1999), the blockbuster action thriller that broke Korean box-office records, and made Kim an instant celebrity throughout Korea. Over the next several years, she starred in five additional films. In July 2003, Kim signed a three-year contract with William Morris, a famous American agency representing Hollywood stars such as Halle Berry, Salma Hayek, Kevin Spacey, Sarah Michelle Gellar, Lucy Liu, Jackie Chan, and Reese Witherspoon.

Kim (credited as Yunjin Kim) can currently be seen as the character Sun in the television series Lost (2004). She has also been cast as the lead actress in the American film Georgia Heat, set to start filming in June 2005. The film will star Billy Bob Thornton and be produced by Janet Young, producer of The Joy Luck Club (1993).