Liaoning is a coastal province in Northeastern China that is the smallest, southernmost, and most populous province in the region. With its capital at Shenyang, it is located on the northern shore of the Yellow Sea, and is the northernmost coastal province of the People's Republic of China.

Historically a gateway between China proper and Manchuria, the modern Liaoning province was established as Fengtian or Fengtien Province (奉天省) in 1907 and was renamed Liaoning in 1929. It was also known at that time as Mukden Province for the Manchu name of Shengjing, the former name of Shenyang. Under the Japanese-puppet Manchukuo regime, the province reverted to its 1907 name, but the name Liaoning was restored for a brief time in 1945 and then again in 1954.

Liaoning borders the Yellow Sea (Korea Bay) and Bohai Sea in the south, North Korea's North Pyongan and Chagang provinces in the southeast, Jilin to the northeast, Hebei to the southwest, and Inner Mongolia to the northwest. The Yalu River marks the province's border with North Korea, emptying into the Korea Bay between Dandong in Liaoning and Sinuiju in North Korea. Liaoning is also one of China's leading provinces in research and education. As of 2025, two major cities in Liaoning ranked in the world's top 100 cities (Dalian #42 and Shenyang #82) by scientific research output, as tracked by Nature Index.

Liaoning is named after the Liao River that runs through the province. Ning (宁, "peace") is used frequently in Chinese place names including Ningxia, Xining and Nanning. The current name was first adopted in 1929, and restored in 1954 upon the merging of the Liaoxi ("West Liao") and Liaodong ("East Liao") provinces.

From 4th century BC to 9th century, Liaoning was predominantly settled and administered by Han Chinese regime. Prior to 3rd century BC, Donghu, Gojoseon and Yemaek peoples inhabited Liaoning and later, the state of Yan conquered the area around 300 BC. Two commanderies, Liaodong ("east of the Liao River") and Liaoxi ("west of the Liao River"), were established within the Liaoning region. The Yan city of Xiangping, the center of Liaodong, was located on the site of the present Liaoyang city. As the Han dynasty fell, warlord Gongsun Du and his family established and maintained a semi-independent state based in Liaodong, until it was defeated by Cao Wei in 238. The state, also known as Yan, conducted numerous maritime diplomatic and trade expeditions, and had a lasting influence on Northeast Asian culture despite being short-lived. After the end of Western Jin dynasty, Liaoning was ruled by Xianbei states of the Murong tribe – Former Yan, Later Yan, and Northern Yan. In 436, as Northern Wei seized the Yan capital, Liaodong Peninsula was taken over by Goguryeo. The Tang dynasty annexed the region during the Goguryeo–Tang War.

In the mid 8th century the An Lushan Rebellion broke out, which greatly drained Tang's resources away from its frontiers, and the Bohai gradually expanded into Liaodong. Eventually, Liaoning was conquered by the Khitan Liao dynasty; during the Liao dynasty, the region was divided among the Eastern Capital Circuit (Dongjingdao), the Supreme Capital Circuit (Shangjingdao), the Central Capital Circuit (Zhongjingdao), and the Lower Capital Circuit (Xiajingdao). Under the Jurchen Jin dynasty, most of the area was administered by the Eastern Capital Route (Dongjinglu), while the rest was divided among the Xianping Route, the Supreme Capital Route (Shangjinglu), and the Northern Capital Route (Beijinglu). In 1206, Liaoning was conquered by Genghis Khan, and later was incorporated into the Yuan dynasty, during the eastern part of the region belonged to the Liaoyang Route and Shenyang Route under the Liaoyang Branch Secretariat; the northern area was under the Kaiyuan Route’s Xianping Prefecture; the western area, including Guangning Route, was also subordinate to the Liaoyang Branch Secretariat; while the Jinzhou and Chaoyang regions were part of the Daning Route under the Central Secretariat.

The Ming Empire took control of Liaoning in 1371, just three years after the expulsion of the Mongols from Beijing. Around 1442, a defense wall was constructed to defend the agricultural heartland of the province from a potential threat from the Jurchen-Mongol Oriyanghan (who were Ming's tributaries) from the northwest. Between 1467 and 1468, the wall was expanded to protect the region from the northeast as well, against attacks from Jianzhou Jurchens (who were later to become known as the Manchu people). Although similar in purpose to the Great Wall of China, this "Liaodong Wall" was of a lower-cost design. While stones and tiles were used in some parts, most of the wall was in fact simply an earth dike with moats on both sides.

Despite the Liaodong Wall, the Jurchens conquered Liaodong, or eastern Liaoning, in the early 17th century, decades before the rest of China fell to them. The Jurchen dynasty, styled "Later Jin" before being renamed to Qing, established its capital in 1616–1621 in Xingjing (兴京), which was located outside of the Liaodong Wall in the eastern part of the modern Liaoning Province. It was moved to Dongjing (east of today's Liaoyang, Liaoning), and finally in 1625 to Shengjing (now, Shenyang, Liaoning). Although the main Qing capital was moved from Shengjing to Beijing after it fell to the Qing in 1644, Shengjing retained its importance as a regional capital throughout most of the Qing era.