Ernst Julius Günther Röhm (28 November 1887–1 July 1934) was a veteran German officer of World War I and early member of the Nazi Party, predating Adolf Hitler's membership. He led the Bund Reichskriegsflagge, one of several right-wing militias of the 1920s, and was convicted of high treason for his participation in the 1923 Beer Hall Putsch, but received a suspended sentence. Röhm briefly retired from political life over frustrations in creating a "legal" successor to the then-outlawed Sturmabteilung, serving as an advisor to the Bolivian army before being personally recalled by Hitler in 1930 to lead the reconstituted SA.

Röhm was an open homosexual but remained a member of Hitler's inner circle, using the familiar du ("you") in conversation, and was the only Nazi leader to address him by his first name or the nickname "Adi". However, Röhm's ambition to craft the SA into an anti-capitalist "people's army" under his direct leadership threatened Hitler's alliance with prominent German business groups and was vehemently opposed by the Reichswehr, the professional standing army, who considered the SA an "undisciplined mob" pervaded by "corrupt morals", and rumours began circulating that the SA was planning a coup; in June 1934 President Hindenburg issued an ultimatum threatening to impose martial law, and thus potentially depose the Nazi regime, if Hitler failed to take control of the matter.

Hitler seized the opportunity to consolidate control, conspiring with Nazi leaders opposed to Röhm, notably Hermann Göring and Heinrich Himmler, to eliminate their political rivals. On June 30, the Schutzstaffel and regular police stormed the Hanselbauer Hotel in Munich and Hitler personally placed Röhm and his lieutenants under arrest; most were summarily executed within hours, but Röhm was kept prisoner until the next day. He was offered the choice of suicide but refused, stating: "If I am to be killed, let Adolf do it himself." Ten minutes later he was shot dead by Theodor Eicke and Michael Lippert.