Gerhart Moritz Riegner (Berlin, September 12, 1911 – Geneva, December 3, 2001) was a German activist and the secretary-general of the World Jewish Congress from 1965 to 1983. On August 8, 1942, he dispatched through diplomatic channels the famous Riegner Telegram to Stephen Samuel Wise, president of the World Jewish Congress. The source of the information was Eduard Schulte, the anti-Nazi chief executive officer of the prominent German company Giesche (part of Silesian-American Corporation) that employed high-level Nazi officials.
The Reigner Telegram was the first official communication notifying the Holocaust. It is cited in the novel The Wallenberg Dossier.