特拉法加海战（法语：Bataille de Trafalgar，英语：Battle of Trafalgar。也译作特拉法尔加海战），1803年拿破仑统治的法国与英国为首的反法联盟再次爆发战争，拿破仑计划进军英国本土，为牵制住强大的英国海军，拿破仑派海军中将维尔纳夫率领的法国和西班牙联合舰队与英国海军周旋。1805年10月21日，双方舰队在西班牙特拉法加角外海面相遇，决战不可避免，战斗持续5小时，由于英军指挥、战术及训练皆胜一筹，法西联合舰队遭受决定性打击，主帅维尔纳夫以及21艘战舰被俘，但英军主帅霍雷肖·纳尔逊海军中将也在战斗中阵亡。

The Battle of Trafalgar (21 October 1805) was a naval engagement fought by the Royal Navy against the combined fleets of the French and Spanish Navies, during the War of the Third Coalition (August–December 1805) of the Napoleonic Wars (1803–1815).

Twenty-seven British ships of the line led by Admiral Lord Nelson aboard HMS Victory defeated thirty-three French and Spanish ships of the line under the French Admiral Villeneuve in the Atlantic off the southwest coast of Spain, just west of Cape Trafalgar, in Caños de Meca. The Franco-Spanish fleet lost twenty-two ships, without a single British vessel being lost. It was the most decisive naval battle of the war, conclusively ending French plans to invade England.