Masanobu Tsuji (? ??, Tsuji Masanobu, 11 October 1901 – ca.1961) was a Japanese army officer and politician.
During World War II, he was an important tactical planner in the Imperial Japanese Army; he developed the detailed plans for the successful Japanese invasion of Malaya at the start of the war.
He also helped plan and lead the final Japanese offensive during the Guadalcanal Campaign.
Tsuji was deeply involved in Japanese atrocities throughout the war, including Bataan Death March and Sook Ching.
He evaded prosecution for war crimes at the end of the war, living in hiding in Thailand.
He returned to Japan in 1949 and was elected to the Diet as an advocate of renewed militarism.
In 1961, he disappeared on a trip to Laos.Tsuji was among the most aggressive and influential Japanese militarists.
He was a leading proponent of the concept of gekokujo, "leading from below" or "loyal insubordination" by acting without or contrary to authorization.
He incited the 1939 border clash with the USSR and was a vehement advocate of war with the United States.