Walther Immanuel Funk (18 August 1890 – 31 May 1960) was a German economist, Nazi official and convicted war criminal who served as Reichsminister for the Economy from 1938 to 1945 and president of the Reichsbank from 1939 to 1945. Funk oversaw the mobilization of the economy for Germany's rearmament and World War II, and the expropriation of assets of victims from Nazi concentration camps. He was convicted for crimes against humanity by the Nuremberg Tribunal.

Funk was a finance journalist before joining the Nazi Party in 1931 and being appointed to a senior post at the Ministry of Public Enlightenment and Propaganda. Funk was appointed as economics minister by Adolf Hitler to replace Hjalmar Schacht, as well as a member of the Council of Ministers for the Defense of the Reich and the Central Planning Board. Funk served as economics minister for nearly all of World War II until he was removed on 5 May 1945 after being left out of the Flensburg Government.

Funk was tried and convicted as a major war criminal by the International Military Tribunal at Nuremberg after the war and sentenced to life in prison. Funk was incarcerated in West Berlin until he was released on health grounds in 1957 and died three years later.

Walther Immanuel Funk was born on 18 August 1890 in Danzkehmen (present-day Sosnovka in Kaliningrad Oblast, Russia) near Trakehnen, East Prussia, the son of merchant and entrepreneur Walther Funk and his wife Sophie (née Urbschat). He was the only one of the Nuremberg defendants who was born in the former eastern territories of Germany. Funk studied law, economics, and philosophy at the University of Berlin and the University of Leipzig, receiving his law doctorate in 1912. He subsequently trained as a journalist at newspapers National-Zeitung in Berlin and Leipziger Neueste Nachrichten in Leipzig.

Following the outbreak of World War I in 1914, Funk enlisted in the Imperial German Army and joined the infantry. He was wounded in action and subsequently discharged as medically unfit for service in 1916. Following the end of the war in 1918, he worked as a journalist, and in 1924 he became the editor of the centre-right financial newspaper the Berliner Börsenzeitung. In 1920, Funk married Luise Schmidt-Sieben.

Funk, who was a nationalist and anti-Marxist, resigned from the Berliner Börsenzeitung in the summer of 1931 and joined the Nazi Party, becoming close to Gregor Strasser, who arranged his first meeting with Adolf Hitler. Partially because of his interest in economic policy, he was elected a Reichstag deputy in July 1932 and made chairman of the party's Committee on Economic Policy in December 1932, a post that he did not hold for long. After the Nazi Party came to power in 1933, he stepped down from his Reichstag position and was made Reich Chief Press Officer under Joseph Goebbels. The post involved censorship of anything deemed critical of Nazi policies.

In March 1933, Funk was appointed as a State Secretary (Staatssekretär) at the Reich Ministry of Public Enlightenment and Propaganda. In the summer of 1936, when Hitler commissioned Albert Speer for the rebuilding of central Berlin, it was Funk who proposed his new title of "Inspector-General of Buildings for the Renovation of the Reich Capital".

On 5 February 1938, Funk became General Plenipotentiary for Economics (Generalbevollmächtigter für die Wirtschaft), as well as Reichsminister for the Economy to permanently replace Hjalmar Schacht who had resigned on 26 November 1937. Funk also succeeded Schacht as Minister of Economics and Labor of Prussia (Preußischer Minister für Wirtschaft und Arbeit) and as an ex officio member of the Prussian State Council. He would hold all these posts until the fall of the Nazi regime. Schacht had been engaged in a power struggle with Reichsmarschall Hermann Göring, who wanted to tie the economics ministry more closely to his Four Year Plan Office. Göring briefly served as Schacht's immediate successor between November 1937 and January 1938 until Funk's appointment. Schacht, who knew Funk well, said he was "extraordinarily musical" being "a first-rate connoisseur of music whose personal preferences in life were decidedly for the artistic and literary." At a dinner when he sat next to Funk, the orchestra played a melody by Franz Lehár. Funk remarked "Ah! Lehár – the Fuhrer is particularly fond of his music." Schacht replied, jokingly, "It's a pity that Lehár is married to a Jewess", to which Funk immediately responded, "That's something the Fuhrer must not know on any account!" Speer relates how Hitler played for him a record of Franz Liszt's Les Préludes and said "This is going to be our victory fanfare for the Russian campaign. Funk chose it!"