Walther Hewel (25 March 1904 – 2 May 1945) was an early and active member of the Nazi Party who became a German diplomat, an SS-Brigadeführer and one of German dictator Adolf Hitler's personal friends. He served as the liaison officer between Reichsminister for Foreign Affairs Joachim von Ribbentrop and Hitler's headquarters. Present in the Führerbunker during the Battle of Berlin, he committed suicide while attempting to escape the Red Army after the breakout from the bunker.

Hewel was born in 1904 to Anton and Elsa Hewel in Cologne in the Rhineland, where his father ran a cocoa factory. His father died in 1913, leaving Elsa to run the factory.

Hewel attended the Gymnasium in Cologne and passed his Abitur in 1923. He went on to attend the Technical University of Munich. That autumn, he joined the Stosstrupp Hitler, a formation of the Nazi Party's SA "brownshirt" stormtroopers – his member number was in the low 200s – and took part in Hitler's failed Beer Hall Putsch, carrying a swastika banner with 23-year-old Heinrich Himmler. As a participant in this event, he would later be awarded the Blood Order. After Hitler's subsequent conviction for treason, Hewel was in Landsberg prison with him for several months, where he served as Hitler's volunteer valet. He was released on 30 December 1924 because of his youth.

Hewel then served a commercial apprenticeship in Hamburg in 1926, following which he spent a year in England. From 1927, Hewel worked abroad for several years in the Dutch East Indies (now Indonesia) as a planter and coffee salesman for a British firm. Hewel joined the Nazi Party there in June 1933 and helped to organise local branches with German expatriates as members. By 1937, the Nazi Party in Indonesia had established branches in Batavia, Bandung, Semarang, Surabaya, Medan, Padang, and Makassar.^{[citation needed]}

In 1936, Hewel returned to Germany, where he was appointed the chief of the East Asia Desk in the Foreign Section of the Party. He entered Germany's diplomatic service and was sent to Spain. Journalist James P. O'Donnell remarked that, during this time, Hewel "was almost certainly an agent of Admiral Wilhelm Canaris's Abwehr" counter-intelligence agency.

Hewel returned to Germany and, in August 1937, became the chief of the English Desk in the office of Ambassador Joachim von Ribbentrop. In February 1938, Ribbentrop became Reichsminister for Foreign Affairs and, in June, Hewel was named head of Ribbentrop's personal staff with the rank of Legation Councilor. On 15 March 1939, he transcribed the conference between Hitler and Czech President Emil Hácha.

Hewel joined the SS as an SS-Sturmbannführer on 12 July 1937, and attained the rank of SS-Brigadeführer on 9 November 1942.

After the outbreak of the Second World War, Hitler was often at his field headquarters away from Berlin. In September 1940, Hewel was appointed the Permanent Representative of the Reichsminister for Foreign Affairs to the Führer, in effect, the liaison officer between Ribbentrop and Hitler's headquarters. During this time, he resumed his earlier friendship with the dictator. He spent most of World War II without an official portfolio and once described himself as "an ambassador to nowhere". In the later years of the war, as Hitler became more estranged from Ribbentrop, Hewel acted as Hitler's senior adviser on foreign policy matters and a member of Hitler's inner circle. On 31 March 1943, Hewel was raised to the rank of Ambassador for special assignments. When Hitler moved from his "Wolf's Lair" headquarters in East Prussia to the Führerbunker under the garden of the Reich Chancellery in Berlin, Hewel joined him there with the rest of Hitler's entourage.