Abstract: A size adjustable hat or cap has a generally round headpiece which covers a portion of the wearer's head, and a rear opening to allow the headpiece to be adjusted to fit the wearer's head. A decorative adjustment mechanism connected to the headpiece allows the rear opening to adjust the headpiece to fit the wearer's head. The headpiece adjustment is achieved with a sizing tie having two segments attached to lower edge of the headpiece. The sizing tie extends rearwardly of the headpiece and is adjusted by a tie lock which moves along the sizing tie to adjust the fit of the headpiece upon a wearer's head by adjusting the rear opening. The sizing tie is provided with a visually pleasing decorative design on is outside surface to establish the dual utilitarian and decorative role of the tie.