In military terms, 121st Division or 121st Infantry Division may refer to:
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121st Infantry Division (German Empire)
The 121st Infantry Division (''121. Infanterie-Division'') was a formation of the Imperial German Army in World War I. The division was formed on March 25, 1915, and organized over the next several weeks. It was part of a wave of new infantry div ...
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121st Infantry Division (Germany)
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121st Division (Imperial Japanese Army)
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121st Rifle Division
The 121st Rifle Division () was an infantry division of the Red Army during World War II.
Formed in September 1939 in Belarus, the division participated in the Soviet invasion of Poland later that month and in the June 1940 occupation of Lithuani ...
(Soviet Union)
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121st Guards Rifle Division (Soviet Union)
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sl:Seznam divizij po zaporednih številkah (100. - 149.)#121. divizija