घोड्यावर स्वार होवून युद्धात भाग घेणाऱ्या सैन्यदलास घोडदळ म्हणतात. घोडेस्वारांस अधिक शस्त्रास्त्रे व चिलखते वाहून नेणे तसेच वेगांत कूच करणे सोपे असल्यामूळे पायदळापेक्षा घोडदळाची कार्यक्षमता जास्त असते.

Historically, cavalry are soldiers or warriors who fight mounted on horseback. Until the 20th century cavalry were the most mobile of the combat arms, operating as light cavalry in the roles of reconnaissance, screening, and skirmishing in many armies, or as heavy cavalry for decisive shock attacks in other armies. An individual soldier in the cavalry is known by a number of designations depending on era and tactics, such as a cavalryman, horseman, trooper, cataphract, knight, drabant, hussar, uhlan, mamluk, cuirassier, lancer, dragoon, or horse archer. The designation of cavalry was not usually given to any military forces that used other animals for mounts, such as camels or elephants. Infantry who moved on horseback, but dismounted to fight on foot, were known in the early 17th to the early 18th century as dragoons, a class of mounted infantry which in most armies later evolved into standard cavalry while retaining their historic designation.