| Yoon Won-hyeong | |
| Office: | Chief State Councillor |
| Term Start: | 9 February 1563 |
| Term End: | 9 September 1565 |
| Predecessor: | Sang Jin |
| Successor: | Yi Jun-gyeong |
| Office1: | Right State Councillor |
| Term Start1: | 15 June 1558 |
| Term End1: | 16 November 1558 |
| Predecessor1: | Yoon Gae |
| Successor1: | An Hyeon |
| Term Start2: | 14 October 1551 |
| Term End2: | 17 October 1551 |
| Predecessor2: | Sang Jin |
| Successor2: | Yoon Gae |
| Birth Date: | 1509 |
| Birth Place: | Joseon |
| Death Place: | Gangeum-hyeon, Paju, Gyeonggi Province, Joseon |
| Country: | Joseon |
Yun Won-hyeong (Korean: 윤원형, 尹元衡; 1509 – 18 November 1565) was a Korean political figure of the Joseon period. He was the younger brother of Queen Munjeong, the 3rd wife of the 11th King Jungjong of Joseon and was the maternal uncle of the 13th King Myeongjong.
He was Chief State Councillor from 1563 to 1565. His courtesy name was Eonpyung . In 1565, after the death of Queen Munjeong, both Yun Won-hyeong and his wife, Jeong Nan-jeong, were exiled from the capital. Unable to make a political comeback, both committed suicide by poison.
In 1509, Yun Won-hyeong was born as the fourth son and youngest child of Yun Ji-im and Lady Lee of the Jeonui Lee clan. He was the younger brother of Queen Munjeong and a third cousin of Queen Janggyeong and Yun Im. He was also the great-great-grandnephew of Queen Jeonghui, who was the wife of Sejo of Joseon, the 7th King of Joseon. At 2-years-old, Yun’s mother died.
Yun Won-hyeong was a political figure from an aristocratic family and of maternal relation of the royal family of the Joseon Dynasty. His family was of the Papyeong Yun clan . His niece, Royal Noble Consort Suk,[1] later became a concubine to King Injong.[2]
In March 1515, Jungjong's second wife, Queen Janggyeong died and Jungjong formally married Yun Won-hyeong's older sister, Lady Yun, to be the new Queen Consort. Their son was Grand Prince Gyeongwon (the future King Myeongjong).
In 1533, Yun Won-hyeong passed the national examinations, and was appointed to the literature department of Byeol to become an officer. While pursuing an officer position, Yun also sought to make his nephew, Grand Prince Gyeongwon, the next king of Joseon. Yun was temporarily exiled for his actions but came back in 1544. He ran into some conflicts with two relatives who were officials: Yun Im and Kim Ahn-ro.
This made for a difficult situation, since Kim Ahn-ro's granddaughter (the daughter of Princess Hyohye and his son, Kim Hui) had married Yun Won-hyeong's own nephew, Yun Baek-won. Also, Yun Im was the maternal uncle of Injong and the older brother of Queen Janggyeong.
In 1543, King Jungjong died. In 1545, King Injong died. Yun Won-hyeong killed his opponents and relatives that supported his third cousin, among these being Yun Im. Later, his brother Yun Won-ro was killed (the Eulsa massacre). In 1546, he controlled political powers. In 1547, he became Minister of Personnel (Ijo Panseo), in 1551 Left State Councillor, and in 1563, Chief State Councillor.
When Queen Munjeong died in 1565, he lost all political power. This caused him and his second wife, Jeong Nan-Jeong to commit suicide.