The naval Battle of Lagos took place on 19 August 1759 during the Seven Years' War off the coasts of Spain and Portugal.

The task of blockading M. de la Clue at Toulon was given to Edward Boscawen, who had with him fourteen sail of the line. Boscawen reached his station on the 16th of May 1759. At the beginning of July want of stores and water, together with the injury inflicted on some of his vessels by a French battery, compelled him to go to Gibraltar to provision and refit. He reached the port on the 4th of August. On the 5th M. de la Clue left Toulon, and on the 17th passed the straits of Gibraltar, where he was sighted by the look-out ships of Boscawen.

The British fleet hurried out to sea, and pursued in two divisions, separated by a distance of some miles owing to the haste with which they left port. During the night of the 17th and 18th of August five of M. de la Clue's ships lost sight of his flagship, and steered for Cadiz. The other seven, which had been delayed for a time in the hope of rejoining their consorts, were overtaken by Boscawen and attacked in the afternoon of the 18th. One, the Centaur (74), was captured after a very gallant resistance, in which the British flagship was severely damaged.

During the night of the 18th/19th of August, two of the French ships altered course to the west, and escaped. The remaining four fled to the north, and into Portuguese waters, where two were driven ashore and destroyed, while two were captured near Lagos. The five in Cadiz were blockaded by Boscawen's second-in-command, Admiral Broderick. La Clue was mortally wounded, and died ashore in Portugal. Although the defeat of his squadron had ruined the scheme for the combination of their forces, the French ministers decided to persevere with their planned invasion of the British Isles.