Mauritius campaign of 1809–1811: A French frigate squadron under Guy-Victor Duperré defeated a convoy of three British East Indiamen near the Comoro Islands.

The Mauritius campaign of 1809–1811 was a minor military campaign of the Napoleonic Wars fought between British and French forces over France's Indian Ocean colonies of Isle de France and Isle Bonaparte. Lasting from the spring of 1809 to the spring of 1811, the campaign saw the British and French navies deploy substantial frigate squadrons to either protect or disrupt British-flagged shipping in the region. In a war in which the Royal Navy was almost universally dominant at sea, the campaign is especially notable for the local superiority enjoyed by the French Navy in autumn 1810 following their victory at the Battle of Grand Port, the British navy's most significant defeat in the entire conflict.