Joachim Friedrich von Blumenthal (1609–1657) was a German nobleman of the von Blumenthal family. He was a diplomat and the founder of the Brandenburg-Prussian Army.
He was born in 1609 and educated at the Viadrina. He was an Imperial War Commissar, as well as both Brandenburg and the Holy Roman Empire's representative at the Peace of Westphalia of 1648, where he negotiated Brandenburg's acquisition of Halberstadt and other territories. He was several times Brandenburg's representative at Imperial Diets. He became the Great Elector's President of the Privy Council (Prime Minister) and it was in this capacity that he raised the finances and organized the system under which a permanent standing army could be created for the first time. He was the first secular governor of the Principality of Halberstadt.
A minister of the "Great Elector", Friedrich Wilhelm (Wilhelm was the great grandfather of Frederick the Great), von Blumenthal had profited handsomely from the war, and remodeled Stavenow Castle in the Baroque style.