The Battle of Alton, of the First English Civil War, took place on 13 December 1643 in the town of Alton, Hampshire, England. There, Parliamentary forces serving under Sir William Waller led a successful surprise attack on a winter garrison of Royalist infantry and cavalry serving under the Earl of Crawford. The Battle of Alton was the first decisive defeat of Sir Ralph Hopton, leader of Royalist forces in the south, and the event had a significant psychological effect on him as commander. More important to Hopton was the loss of men, however, as he was already short-handed in much-needed infantry. The successful Parliamentarians were able, after their victory, to attack and successfully besiege Arundel, a larger and more formidable Royalist outpost to the south-east of Alton.