Yoon Yong-Il (born September 23, 1973, in Daegu, South Korea) is a former professional South Korean tennis player.

Yoon reached his highest individual ranking on the ATP Tour on December 18, 2000, when he became World number 140. He played primarily on the Futures circuit and the Challenger circuit.

Yoon was a member of the South Korean Davis Cup team, posting a 16–10 record in singles and a 3–4 record in doubles in sixteen ties played.

Outcome	No.	Date	Tournament	Surface	Opponent in the final	Score
Winner	1.	September 23, 1996	Beijing, China	Hard	Xia Jiaping	6–4, 2–6, 6–1
Winner	2.	May 4, 1998	Beijing, China	Hard	Hideki Kaneko	6–3, 7–5
Runner-up	1.	May 11, 1998	Tianjin, China	Hard	Hideki Kaneko	4–6, 7–6, 0–6
Runner-up	2.	October 5, 1998	Maishima, Japan	Carpet	Lee Hyung-Taik	6–7, 6–2, 4–6
Winner	3.	July 5, 1999	Jakarta, Indonesia	Clay	Rik De Voest	7–6, 7–5
Runner-up	3.	July 26, 1999	St. Joseph, U.S.	Hard	Thomas Dupré	6–4, 4–6, 1–6
Winner	4.	August 9, 1999	Kansas City, U.S.	Hard	David Nalbandian	6–3, 6–7, 6–2
Winner	5.	February 28, 2000	Jakarta, Indonesia	Hard	Kwon Oh-hee	6–2, 6–4
Runner-up	4.	May 8, 2000	Fukuoka, Japan	Grass	Takahiro Terachi	6–2, 6–7, 1–6
Winner	6.	May 15, 2000	Osaka, Japan	Hard	Paul Baccanello	6–4, 6–7, 6–4
Runner-up	5.	May 22, 2000	Seoul, South Korea	Clay	Park Seung-kyu	5–7, 6–7
Runner-up	6.	July 24, 2000	Winnetka, U.S.	Hard	Takao Suzuki	2–6, 4–6
Runner-up	7.	August 7, 2000	Binghamton, U.S.	Hard	Takao Suzuki	1–6, 4–6
Runner-up	8.	November 27, 2000	Manila, Philippines	Hard	Zbynek Mlynarik	6–4, 0–6, 2–6
Runner-up	9.	December 4, 2000	Manila, Philippines	Hard	Danai Udomchoke	3–6, 6–3, 5–7
Winner	7.	April 21, 2003	Kumamoto, Japan	Hard	Benjamin Kohllöffel	6–3, 6–2
Runner-up	10.	December 12, 2003	Seogwipo, South Korea	Clay	Takahiro Terachi	0–6, 5–7

• Yoon Yong-il at the Association of Tennis Professionals
• Yoon Yong-il at the International Tennis Federation
• Yoon Yong-il at the Davis Cup