The siege of Antwerp was an engagement between the German and the Belgian, British and French armies around the fortified city of Antwerp during World War I. German troops besieged a garrison of Belgian fortress troops, the Belgian field army and the British Royal Naval Division in the Antwerp area, after the German invasion of Belgium in August 1914. The city, which was ringed by forts known as the National Redoubt, was besieged to the south and east by German forces.

Antwerp is a city and a municipality in the Flemish Region of Belgium. It is the capital and largest city of Antwerp Province, and the third largest city in Belgium by area at 204.51 km2 (78.96 sq mi) after Tournai and Couvin. With a population of 536,079, it is the most populous municipality in Belgium, and with a metropolitan population of over 1,200,000 people, the country's second-largest metropolitan region after Brussels.