Heidenreich John Emmanuilovich (b. 1905 — exact date and place of birth unknown) – Bolshevik, Soviet diplomat, and party official.

In 1921, as a member of the Komsomol, John Heidenreich voluntarily joined the Red Army. In 1924, he became a member of the All-Union Communist Party (Bolsheviks) as part of Lenin's call for party expansion. In 1931, he was assigned by the Party Central Committee to the People’s Commissariat for Foreign Affairs, and in 1932 was posted to China. He managed the confidential cipher department of the Soviet Consulate and was elected secretary of the party organisation of the Soviet colony there.

John Heidenreich played an active role in the Xinjiang campaign and undertook a number of operational assignments. He continued to work at the Commissariat of Foreign Affairs until December 1937, serving for an extended period as Vice-Consul.

Between 1938 and 1941, Heidenreich worked in the aviation industry and was elected secretary of a primary party organisation. In July 1941, he was appointed commissar of a sector at the Department of Defensive Works of the NKVD on the Northwestern Front. From 1942, he served in the Soviet Army as a liaison officer in the 14th and 27th Guards Rifle Corps.

He was severely wounded and concussed after stepping on a landmine near Prague. Demobilised in 1946 due to disability, he then worked in Riga as a shop supervisor at the Rīga Electric Plant (REZ), and later as head of supply and sales at the “Rīgas Jūrmala” fish processing plant. In 1955–1956, he worked from home for the Dzimtene artel and the Straume plant.

John Heidenreich was awarded the Order of the Red Star, the Medal for the Victory over Germany in the Great Patriotic War 1941–1945, and, in 1967, the Medal for Labour Distinction. He was designated a personal pensioner of republican significance.