Abstract: The hat wig is an article of headwear, such as a hat, cap or the like, with hair extending from the interior of the headwear so that the appearance of a hat placed on top of a full head of hair is created when the hat wig is worn. The top ends of the hair are secured in a soft fabric band that is peripherally disposed about at least a portion of the base of the interior of the headwear and permanently fastened thereto in a manner that conceals the band from outside viewing and allows the hair to freely depend downward from the band. The hat wig is highly customizable and can be adapted to several types of headwear, including a hat of the wearer's choosing. Moreover, real or synthetic hair of various styles, lengths, and types can be used to suit the taste of the wearer.