The Liaodong Peninsula (simplified Chinese: 辽东半岛; traditional Chinese: 遼東半島; pinyin: Liáodōng Bàndǎo) is a peninsula in southern Liaoning province in Northeast China, and makes up the southwestern/coastal half of the Liaodong region. It is located between the mouths of the Daliao River (the historical lower section of the Liao River) in the west and the Yalu River in the east, and encompasses the territories of the whole sub-provincial city of Dalian and parts of prefectural cities of Yingkou, Anshan and Dandong.

The word “Liaodong” (formerly spelled Liaotung) literally means “east of the Liao region”, referring to the Warring States period Yan commandery of Liaodong, which encompassed an area from modern Liaoning-Jilin border in the north to the Chongchon River in the south, and from just east of the Qian Mountains to the Daling River in the west. The modern usage of “Liaodong” however simply refers to the half of Liaoning province that is east of the Liao River.