The Eighth Route Army (Balu Jun), also known as the 18th Army Group of the National Revolutionary Army of the Republic of China, was a group army under the command of the Chinese Communist Party, nominally within the structure of the Chinese military headed by the Chinese Nationalist Party during the Second Sino-Japanese War.

The Eighth Route Army was created from the Chinese Red Army on September 22, 1937, when the Chinese Communists and Chinese Nationalist Party formed the Second United Front against Japan at the outbreak of the Second Sino-Japanese War, as World War II is known in China. Together with the New Fourth Army, the Eighth Route Army formed the main Communist fighting force during the war and was commanded by Communist party leader Mao Zedong and general Zhu De.