Smart casual

An example of smart casual attire with a blazer.

Smart casual is an ambiguously defined Western dress code that is generally considered casual wear but with smart (in the sense of "well dressed") components of a proper lounge suit from traditional informal wear. For men, this interpretation typically includes a dress shirt, necktie, trousers, and dress shoes, possibly worn with an odd-coloured blazer or a sports coat.

Smart casual formed as a dress code in the 20th century, originally designating a lounge suit of unconventional colour and less heavy and thus more casual fabric, possibly with more casual cut and details. As the one-coloured lounge suit came to define informal wear, thus uneven colours became associated with smart casual. The definition of smart casual and business casual thus became virtually undistinguishable from the 1950s, implying a more casual suit than the traditional, usual dark suit in heavy cloth.

Since the counterculture of the 1960s in the Western world, different Western cultures and events can have varying expectations of the dress code, especially with regards to necktie, and in warmer climates sometimes even with regards to a jacket at all. Therefore, the designation of certain clothing pieces as smart casual is disputed, as is its distinction, if any, from business casual.