The Battle of Portland, also known as the Three Days' Battle, was a naval battle of the First Anglo-Dutch War. On 28 February 1653, the fleet of the Commonwealth of England under General at Sea Robert Blake attacked the fleet of the United Provinces under Admiral Maarten Tromp as he escorted merchantmen through the English Channel. Tromp lost fifty merchant vessels and twelve warships, but escaped through good manoeuvering. Blake was wounded during the battle.

The third day of fighting, off Beachy Head on 2 March 1653, is known as the Battle of Beachy Head.