The siege of San Andreas also known as the siege of Sint-Andries was a military event that took place during the Eighty Years' War and the Anglo–Spanish War from 28 January to 6 March 1600. The Spanish garrison of San Andreas was besieged by an Anglo-Dutch force led by Maurice of Nassau. A Spanish relief force under the command of Luis de Velasco failed to relieve the fort after having been turned back by the besiegers. The fort surrendered after the garrison mutinied and accepted payment from Maurice.

Maurice of Orange was stadtholder of all the provinces of the Dutch Republic except for Friesland from 1585 at the earliest until his death in 1625. Before he became Prince of Orange upon the death of his eldest half-brother Philip William in 1618, he was known as Maurice of Nassau.