Lieutenant General Nils Axel Hjalmar Björk (25 February 1898 – 15 April 1989) was a senior Swedish Army officer.

He was promoted to lieutenant in 1920 and attended the Royal Swedish Army Staff College from 1925 to 1927 and transferred to Västernorrland Regiment (I 21) in 1928 after I 18 was disbanded.

[2] Björk was one of the contributors to Antingen – eller ("Either – Or"), which was of fundamental importance for the rearmament work and the Defence Act of 1936.

[3] He served in Svea Life Guards in 1937 and became major in the General Staff Corps in 1938.

Björk succeeded lieutenant colonel Carl August Ehrensvärd as head of Army Operations Department in the Defence Staff in 1939 and in this position had the immediate responsibility for the planning of the extensive operational contingency measures for the Swedish Army during the war years 1939–1942.