The 5th Pri-Amur Corps (Russian: 5-й Приамурский корпус) was a formation of the Siberian Army, part of the anti-Bolshevik White movement during the Russian Civil War. It primarily operated in the Transbaikal region and was headquartered in the city of Chita. The 5th Corps was formed from the Transbaikal Cossacks and various other volunteer forces fighting under Ataman (chief) Grigory Semyonov, as part of his Special Manchurian Unit (Особый маньчжурский отряд, OMO).
After Grigory Semyonov's OMO, based in Chita and sponsored by Japanese intervention forces, made contact with the Provisional Siberian Government under Pyotr Vologodsky in September 1918, he was promoted by the Omsk government's war minister Pavel Ivanov-Rinov to the rank of colonel and was designated as the commander of the 5th Pri-Amur Army Corps. The OMO and other units in the Russian Far East were subordinated to the new 5th Corps. The unit received equipment and money from the Japanese, including rifles, ammunition, field guns, and clothing. In addition to artillery, the 5th Corps also operated eight aircraft and several armored trains. There was friction between Semyonov's loyalists in the OMO and the other units of the 5th Corps that were more loyal to the Provisional Siberian Government, and they viewed each other with suspicion. When Admiral Alexander Kolchak, a rival of the ataman and his Japanese backers, took control of the Siberian government in a coup, the hostility between the two factions escalated. Semyonov blocked telegraph communications between Omsk and Vladivostok, and refused to follow his orders. In December 1918 Kolchak issued Directive No. 60 which accused Semyonov of banditry and atrocities, removing him from command of the 5th Corps. In mid-December, Semyonov renamed the 5th Pri-Amur Corps to the "Separate Eastern Siberian Army" and went under that name, with the 5th Corps being dissolved.