Cho Yoon-jeong (Korean: 조윤정, born 2 April 1979) is a former South Koreantennis player. Cho won one doubles title during her career on the WTA Tour, at Seoul in 2004. Her best Grand Slam performance was when she made the third round of the 2005 U.S. Open, by defeating Arantxa Parra Santonja in three sets in the first round, upsetting the 27th seed Gisela Dulko in the second round, and fell, 6–0, 6–7(4) to number 7 Justine Henin-Hardenne. She reached career-high rankings of No. 45 in singes (in July 2003), and No. 98 in doubles (in September 2003). Cho Yoon-jeong retired from tennis 2008.