The Yorktown or Virginia campaign was a series of military maneuvers and battles during the American Revolutionary War that culminated in the siege of Yorktown in October 1781. The result of the campaign was the surrender of the British Army force of General Charles Earl Cornwallis, an event that led directly to the beginning of serious peace negotiations and the eventual end of the war. The campaign was marked by disagreements, indecision, and miscommunication on the part of British leaders, and by a remarkable set of cooperative decisions, at times in violation of orders, by the French and Americans.

The campaign involved land and naval forces of Great Britain and France, and land forces of the United States. British forces were sent to Virginia between January and April 1781 and joined with Cornwallis's army in May, which came north from an extended campaign through the southern states. These forces were first opposed weakly by Virginia militia, but General George Washington sent first Marquis de Lafayette and then "Mad" Anthony Wayne with Continental Army troops to oppose the raiding and economic havoc the British were wreaking. The combined American forces, however, were insufficient in number to oppose the combined British forces, and it was only after a series of controversially confusing orders by General Sir Henry Clinton, the British commander-in-chief, that Cornwallis moved to Yorktown in July and built a defensive position that was strong against the land forces he then faced, but was vulnerable to naval blockade and siege.

British naval forces in North America and the West Indies were weaker than the combined fleets of France and Spain, and, after some critical decisions and tactical missteps by British naval commanders, the French fleet of Paul de Grasse gained control over Chesapeake Bay, blockading Cornwallis from naval support and delivering additional land forces to blockade him on land. The Royal Navy attempted to dispute this control, but Admiral Thomas Graves was defeated in the key Battle of the Chesapeake on September 5. American and French armies that had massed outside New York City began moving south in late August, and arrived near Yorktown in mid-September. Deceptions about their movement successfully delayed attempts by Clinton to send more troops to Cornwallis.

The siege of Yorktown began on September 28, 1781. In a step that probably shortened the siege, Cornwallis decided to abandon parts of his outer defenses, and the besiegers successfully stormed two of his redoubts. When it became clear that his position was untenable, Cornwallis opened negotiations on October 17 and surrendered two days later. When the news reached London, the government of Lord North fell, and the following Rockingham ministry entered into peace negotiations. These culminated in the Treaty of Paris in 1783, in which King George III recognized the independent United States of America. Clinton and Cornwallis engaged in a public war of words defending their roles in the campaign, and British naval command also discussed the navy's shortcomings that led to the defeat.