The Fourth Anglo-Dutch War (; 1780–1784) was a conflict between the Kingdom of Great Britain and the Dutch Republic. The war, contemporary with the War of American Independence (1775–1783), broke out over British and Dutch disagreements on the legality and conduct of Dutch trade with Britain's enemies in that war.
Although the Dutch Republic did not enter into a formal alliance with the rebelling American colonies and their allies, American ambassador (and future president) John Adams managed to establish diplomatic relations with the Dutch Republic, making it the second European country to diplomatically recognise the Continental Congress in April 1782. In October 1782, a treaty of amity and commerce was concluded as well.
Most of the war consisted of a series of British operations against Dutch colonial economic interests, although British and Dutch naval forces also met once off the Dutch coast. The war ended disastrously for the Dutch and exposed the weakness of the political and economic foundations of the republic.
The war settled the decline of the Dutch Empire and further cemented Great Britain as the leading commercial power.
Background
Although Great Britain and the Dutch Republic had been allies since the Glorious Revolution of 1688, the Dutch had become very much the junior partner in the alliance and had slowly lost their former dominance of world trade to the British. During the Second Stadtholderless Period, the Dutch Republic had more or less abdicated its pretences as a major power and this became painfully evident to the rest of Europe during the War of the Austrian Succession. Near the end of that war in 1747, an Orangist revolution restored the stadtholderate with vastly increased powers for the stadtholder and made the stadtholderate hereditary. This did not lead to a resurgence of the republic as a major power because of what many in the republic saw as the mismanagement of the stadtholderian regency during the minority of stadtholder William V, and subsequently during his own reign. Instead, the republic remained stubbornly neutral during the Seven Years' War, which enabled it to greatly neglect both its army and navy. The stadtholderian regime was pro-British, with the stadtholder being a grandson of King George II of Great Britain, but his opponents for this reason favoured France, and those opponents were strong enough in the States General of the Netherlands (the governing body of the Republic whose "first servant" the stadtholder was) to keep Dutch foreign policy neutral.
Initially, the British considered the Dutch allies in their attempt to stamp out the rebellion in their North American Thirteen Colonies. They attempted to "borrow" the mercenary Scots Brigade of the Dutch States Army for use in the Americas, in a similar manner to the Hessian and Brunswicker contingents they hired and deployed. This was strongly opposed by the Dutch sympathizers of the American Revolution, led by Baron Joan van der Capellen tot den Pol, who managed to convince the States General to refuse the British request.
More importantly, Dutch merchants, especially those from Amsterdam, became involved in the supply of arms and munitions to the American rebels soon after the outbreak of American Revolutionary War. This trade was mainly conducted via the Caribbean entrepôt of St. Eustatius, an island colony of the Dutch West India Company. There, American colonial wares, such as tobacco and indigo, were imported, in contravention of the British Navigation Acts) and re-exported to Europe. For their return cargo, the Americans purchased arms, munitions, and naval stores brought to the island by Dutch and French merchants. In 1776 the governor of the island, Johannes de Graeff, was the first to salute the flag of the United States, leading to growing British suspicions of the Dutch. In 1778, the Dutch refused take Britain's side in the war against France. The British invoked a number of old treaties (1678, 1689, 1716) to have the republic support them militarily, but as in the Seven Years' War, the Dutch government refused.