Clothing is an aspect of human physical appearance, and like other aspects of human physical appearance it has social significance. All societies have dress codes, most of which are unwritten but understood by most members of the society. The dress code has built in rules or signals indicating the message being given by a person's clothing and how it is worn. This message may include indications of the person's social class, income, occupation, ethnic and religious affiliation, attitude, marital status, sexual availability and sexual orientation. Clothes convey other social messages including the stating or claiming personal or cultural identity, the establishing, maintaining, or defying social group norms, and appreciating comfort and functionality.

For example, wearing expensive clothes can communicate wealth, the image of wealth, or cheaper access to quality clothing. All factors apply inversely to the wearing of inexpensive clothing and similar goods.The observer sees the resultant, expensive clothes, but may incorrectly perceive the extent to which these factors apply to the person observed. (cf. conspicuous consumption). Clothing can convey a social message, even if none is intended.

If the receiver's code of interpretation differs from the sender's code of communication, misinterpretation follows. In every culture, current fashion governs the manner of consciously constructing, assembling, and wearing clothing to convey a social message. The rate of change of fashion varies, and so modifies the style in wearing clothes and its accessories within months or days, especially in small social groups or in communications media-influenced modern societies. More extensive changes, requiring more time, money, and effort to effect, may span generations. When fashion changes, the messages communicated by clothing change.