Jin Wengong 晉文公 (r. 636-628) was a ruler of the state of Jin 晉 during the Spring and Autumn period 春秋 (770-5th cent. BCE) and the second of the so-called five hegemons (wuba 五霸). His personal name was Ji Chong'er 姬重耳, and he was a son of duke Xian 晉獻公 (r. 676-651), who made him grand master (dafu 大夫) of the town of Pu 蒲 (modern Xixian 隰縣, Shanxi).
During the unrest caused by Li Ji 驪姬, Mingzhong took refuge to the Di 狄 tribes, and to a whole series of states. He stayed abroad for nineteen years and suffered all hardships of the common man. In 636 he was able to return under the protection of an army of Qin 秦 to mount the throne of Jin. He first killed his uncle, Duke Huai 晉懷公 (r. 637), and his ministers Lü Sheng 呂省 and Xi Rui 郤芮.
Through a centralisation of the government he was able to make Jin a powerful state. His first international activity was the re-enthronment of King Xiang of Zhou 周襄王 (r. 651-619). In 632 he defeated the army of Chu 楚 at Chengpu 城濮 (modern Zhengcheng 鄭城, Shandong), a victory that enabled him to assemble the regional rulers (zhuhou 諸侯) at Jiantu 踐土 (modern Yuanyang 原陽, Henan), and, in the presence of the king, he proclaimed himself the hegemonial lord (houbo 侯伯).
Although Duke Wen of Jin was only the second hegemonial lord, after Duke Huan of Qi 齊桓公 (r. 685-643), he was actually the one who institutionalized this position.