A costume designer is a fashion professional who is responsible for creating the look and mood for actors and actresses in film, television and stage productions. The costume designer does this through designing, sewing, researching and purchasing actual clothing and costumes worn by those on stage and by selecting or designing the accessories and props which help to define each character.

A costume designer must be an expert in beauty and style. He/she must have a thorough understanding of film, production, theatre, marketing and fashion design as well as the ability and desire to research and continually learn about scenarios, cultures and periods of history which help demonstrate the director's vision. The costume designer and his/her team must ensure individual props and wardrobes reflect the story being told and portray the character's personalities, cultures, ages, status and relationships. Many costumes may be required for each character as costumes define the attitude and feel which may change with every new scene, setting or development.