Lieutenant General Oscar Fredrik Osterman (5 September 1874 – 3 November 1956) was a senior Swedish Army officer.

Osterman, a graduate of the Military Academy Karlberg in 1894, held various high-ranking positions within the Swedish Army.

Osterman also played a pivotal role in the establishment of the Swedish Association of Army, Navy, and Air Force Officers and served as its first chairman from 1932 to 1936.

[2][6] Osterman was a judicious and skilled technician and a prominent organizer, by nature objective, factual, and thoughtful.

[2][7] Osterman became a member of the Royal Swedish Academy of War Sciences in 1911 and served as its vice president from 1935 to 1937.

[9] They had three children; Märta, Carl-Göran,[10] and Stig Osterman (1905–1950),[11] who worked as an assessor in the Swedish Fiscal Court of Appeal (Kammarrätten).

[14] He declined reelection due to age reasons at the family meeting at Berns salonger in Stockholm in April 1952 and was appointed as the first honorary chairman.