A hair dryer is a electromechanical device designed to blow cool or hot air over wet or damp hair, in order to accelerate the evaporation of water particles and dry the hair. The usage of hair dryers also allows to better control the shape of the hair in the process of styling, by accelerating and controlling the formation of temporary hydrogen bonds inside the hair.

Hair dryers were invented around the end of the 19th century, being dependent on heat generation and mechanical air flow in order to be effective.

Hairstyles using hair dryers usually have volume and discipline, and can be further improved by the usage of brushes during drying to add tension, and usage of styling products.

Before the development of hairdrying, hairstyles tended to be stiff and lacking volume.