The Brunswick Manifesto was a proclamation issued by Charles William Ferdinand, Duke of Brunswick, commander of the Allied army, on 25 July 1792 to the population of Paris, France during the War of the First Coalition. The manifesto threatened that if the French royal family were harmed, then French civilians would be harmed. It was said to have been a measure intended to intimidate Paris, but rather helped further spur the increasingly radical French Revolution and finally led to the war between Revolutionary France and counter-revolutionary monarchies.

Charles William Ferdinand was the prince of Brunswick-Wolfenbüttel and duke of Brunswick-Lüneburg and a military leader. His titles are usually shortened to Duke of Brunswick in English-language sources.