General Seishirō Itagaki (板垣 征四郎, Itagaki Seishirō, 21 January 1885 – 23 December 1948) was a Japanese military officer and politician who served as a general in the Imperial Japanese Army during World War II and War Minister from 1938 to 1939.

He was a disciple of Kanji Ishiwara and his ideas were strongly influenced by his apocalyptic Buddhist beliefs, being firmly convinced of the idea of a "Final War" in which Japan would unite the entire world into a single nation, resulting in an era of true peace, regeneration and harmony.

Itagaki was then transferred to command the IJA 33rd Infantry Regiment in China from 1928 to 1929, under the aegis of the prestigious Kwantung Army.

In 1931, Itagaki rose to become Chief of the Intelligence Section of the Kwantung Army, in which capacity he helped plan the Mukden Incident that led to the Japanese seizure of Manchuria.

On 6 December 1938, Itagaki proposed a national policy in accordance with Hakko Ichiu (Expansion) at the Five Ministers Conference,[5] which was the Japanese highest decision making council,[6][7] and the council made a decision of prohibiting the expulsion of the Jews in Japan, Manchuria, and China as Japanese national policy.

On 7 July 1941, Itagaki was reassigned to command the Chosen Army in Korea, then considered to be a non-prestigious backwater post.

Itagaki surrendered Japanese forces in Southeast Asia to British Admiral Louis Mountbatten in Singapore on 12 September 1945.