The Anglo-Spanish War (1585–1604) was an intermittent conflict between the Habsburg Kingdom of Spain and the Kingdom of England. It was never formally declared. The war included much English privateering against Spanish ships, and several widely separated battles. It began with England's military expedition in 1585 to what was then the Spanish Netherlands under the command of the Earl of Leicester, in support of the Dutch rebellion against Spanish Habsburg rule.

The English enjoyed a victory at Cádiz in 1587, and repelled the Spanish Armada in 1588, but then suffered heavy setbacks: the English Armada (1589), the Drake–Hawkins expedition (1595), and the Essex–Raleigh expedition (1597). Three further Spanish armadas were sent against England and Ireland in 1596, 1597, and 1601, but these likewise ended in failure for Spain, mainly because of adverse weather.

The war became deadlocked around the turn of the 17th century during campaigns in the Netherlands, France, and Ireland. It was brought to an end with the Treaty of London (1604), negotiated between Philip III of Spain and the new king of England, James I. In the treaty, England and Spain agreed to cease their military interventions in the Spanish Netherlands and Ireland, respectively, and the English ended their high seas privateering.