The affair of Fielding and Bylandt is a brief naval engagement off the Isle of Wight on December 31, 1779 between a Royal Navy squadron, commanded by Commodore Charles Fielding, and a naval squadron of the Dutch Republic, commanded by rear-admiral Lodewijk van Bylandt, escorting a Dutch convoy.

The Dutch and British are not yet at war, but the British wish to inspect the Dutch merchantmen for what they consider contraband destined for France, at this time engaged in the American War of Independence.

Bylandt attempts to avoid the engagement by offering the ships' manifests, but when Fielding insists on a physical inspection, Bylandt puts up a brief show of force, before striking his colous.

The British now seize the Dutch merchantmen and conduct  them as prizes to Portsmouth, followed by the Dutch squadron.

The incident worsens the diplomatic relations between Great Britain and the Dutch Republic almost to breaking point.

It also contributes to the formation of the First League of Armed Neutrality to which the Dutch will accede in December, 1780.

To prevent their receiving assistance from other members of that League, Britain will declare the Fourth Anglo-Dutch War shortly afterwards.