Goryeo official who accompanied King Hyeonjong throughout the Khitan invasion; Minister of Revenue and son of the founder Jang Yu

| Life | 954 ~ 1015 |
| Era | 고려 전기 |
| Clan | 흥덕 장씨 |
Jang Yeon-u (954-1015) was an early Goryeo official of the Heungdeok Jang clan and son of its founder Jang Yu. Jang Yu came from Sangjil county (present-day Heungdeok-myeon, Gochang, North Jeolla) in Later Baekje, fled the chaos of the Later Three Kingdoms to Wuyue where he learned Chinese, returned after Taejo unified the peninsula, and under Gwangjong handled Chinese envoys at the Board of Guest Reception. Yeon-u followed his father into Goryeo politics.
When the Khitan invaded in 1011 and burned the royal ancestral shrine and palace, King Hyeonjong fled to Naju. Many officials scattered at the rumor that Ha Gong-jin had been captured, but Jang Yeon-u stayed with the king along with Chae Chung-sun, Ju Jeo, Ryu Jong and Kim Eung-in, and was rewarded with the post of Jungchusa and then Pan Eosadaesa, according to the Goryeosa, vol. 94.
In 1014, with Hwangbo Yu-ui, he proposed taking the stipend land of the capital army to pay officials whose salaries had run short after the invasion. The measure is said to have fed the revolt of generals Choe Jil and Kim Hun, and his name was struck from the register. Reinstated after the revolt, he rose to Minister of Revenue in 1015 and died that year, being posthumously made Sangseo Ubokya. He also appears in the 2023-2024 KBS drama Goryeo-Khitan War.
The founder Jang Yu came from Sangjil county in Later Baekje and served as Gwangpyeong Sirang. Wikipedia traces the place from Sangchil (or Sangchon) county under Baekje, renamed Sangjil in 757, Jangdeok under Hyeonjong of Goryeo and Heungdeok in 1308; other sources give 1298, so the year differs by source.
A memorial hall and spirit-path stele are said to stand in Seongnae-myeon, Gochang.
His 6th-generation descendant Jang Gi was enfeoffed as Prince Heungsan, and the descendants took Heungseong and then Heungdeok as their seat.