The 81st Group Army (Chinese: 第八十一集团军; pinyin: Dì Bāshíyī Jítuánjūn), Unit 31675, formerly the 65th Group Army, is a military formation of the Chinese People's Liberation Army Ground Force (PLAGF).

The 81st Group Army is one of thirteen total group armies of the PLAGF, the largest echelon of ground forces in the People's Republic of China, and one of three assigned to the nation's Central Theater Command.

In 1949 the unit was reorganized and redesignated as the 65th Army under the command of Hsiao Ying-t'ang.

Following the Korean War the 65th Army was redeployed to Hebei in 1953.

In May 1989, the 65th Army’s 193rd and 194th Infantry Divisions along with the 3rd Reserved Division were deployed to Beijing to enforce martial law and suppress the Tiananmen Square protests of 1989.