Jānis Lācis
Born	February 20, 1897 Jaunpiebalga Municipality, Kreis Wenden, Governorate of Livonia, Russian Empire (Now  Latvia)
Died	March 10, 1937(1937-03-10) (aged 40) Khabarovsk, Soviet Union
Allegiance	Russian Empire Soviet Union
Branch	Imperial Russian Army Soviet Red Army
Service years	1916–1917 (Russian Empire) 1917–1937 (Soviet Union)
Rank	Komkor
Commands	15th Rifle Division 16th Rifle Corps
Conflicts	World War I Russian Civil War

Jānis Lācis (Russian: Ян Я́нович Ла́цис, Yan Yanovich Latsis; February 20, 1897 – March 10, 1937) was a Latvian Riflemen, later Soviet division commander and Komkor (corps commander).

Lacis fought in the 4th Vidzeme Latvian Riflemen Regiment of the Imperial Russian Army in World War I before going over to the Bolsheviks in the subsequent civil war. He was a recipient of the Order of Lenin and the Order of the Red Banner. From 1932 to 1937, he commanded the troops guarding the railways of Siberia and the Far East. He was simultaneously a member of the Central Executive Committee of the Russian Soviet Federative Socialist Republic. He died of an illness in Khabarovsk. He is buried at Novodevichy Cemetery.