Formal wear or full dress is the Western dress code category applicable for the most formal occasions, such as weddings, christenings, confirmations, funerals, Easter and Christmas traditions, in addition to certain state dinners, audiences, balls, and horse racing events. Generally permitted other alternatives, though, are the most formal versions of ceremonial dresses, full dress uniforms, religious clothing, national costumes, and most rarely frock coats. In addition, formal wear is often instructed to be worn with official full size orders and medals.

Western dress codes are a set of dress codes detailing what clothes are worn for what occasion. Conversely, since most cultures have intuitively applied some level equivalent to the more formal Western dress code traditions, these dress codes are simply a versatile framework, open to amalgamation of international and local customs. This versatility has made this scale of formality a practical international formality scale.