Aimo Kaarlo Cajander (4 April 1879 – 21 January 1943) was the Prime Minister of Finland up to the Winter War.

[2] Cajander was born in Uusikaupunki, and became a botanist,[3] a professor of forestry 1911–34; director-general for Finland's Forest and Park Service 1934–1943; Prime Minister in 1922, 1924, and 1937–1939; chairman of the National Progressive Party 1933–1943; and Member of Parliament.

When Kyösti Kallio was elected president in 1937, Cajander was asked as the chairman of the National Progressive Party to form majority government.

Cajander formed a coalition government of the two largest parties in the parliament - Social Democrats and Agrarian League.

Cajander's name is remembered for "Model Cajander", the fashion of many Finnish soldiers in Winter War: the army was poorly equipped, so mobilized reserves were given a utility belt, an emblem to be attached to the hat — to comply with the Hague Conventions; and a rifle.