Ahti Kalle Samuli Karjalainen (10 February 1923 – 7 September 1990) was a Finnish politician. He was a member of the Agrarian League (later known as Keskusta, Centre Party) and served two terms as Prime Minister of Finland. He is, however, better known for his period as Minister of Foreign Affairs of Finland. Karjalainen is considered one of the most influential figures in post-war Finnish politics. Like President Urho Kekkonen, Karjalainen attached great importance to Finland's relationship with the Soviet Union.