Baarin Left Banner (Mongolian: ᠪᠠᠭᠠᠷᠢᠨ ᠵᠡᠭᠦᠨ ᠬᠣᠰᠢᠭᠤ; Chinese: 巴林左旗), or Bairin, is a banner of eastern Inner Mongolia, China, under the administration of the prefecture-level city of Chifeng. The banner spans an area of 6,644 square kilometers, and as of 2018, has a population of 340,020. Baarin Mongols live here.^{[citation needed]} The distinct Mongolian dialect of this region is called Baarin.^{[citation needed]} It is located at the intersection of two national highways: China National Highway 303 and 305.

Balin Left Banner has a long history, with archaeological digs dating to the 40th Century BC. Archaeological relics uncovered in the banner are believed to include those of the Hongshan culture and the Fuhe culture.

Around the time China was undergoing the Warring States period, the area of Bairin Left Banner was home to the Shanrong and Donghu people. Later, the area would be home to the Wuhuan and the Xianbei.

During the first few centuries of the Common Era, the area was home to the Khitan people and the Kumo Xi.

In 918 CE, the capital of the Khitan-led Liao Dynasty, Shangjing (Chinese: 上京), was built in present-day Bairin Left Banner. From 918 CE to 938 it was known as Huangdu (皇都).

During the time of the Republic of China, many Han Chinese began moving to the area.

On March 1, 1933, the banner, then known as Lindong County (林东县; 林東縣), was invaded by Japanese forces, who occupied the county until August 10, 1945.

On June 1, 1946, the Chinese Communist Party established its local government in the area, the Lindong Administrative Committee (林东行政委员会; 林東行政委員會).