A hair extension assembly includes an elongated base being sufficiently flexible to conform to the contours of the wearer's head and including an attachment assembly comprising a plurality of loops extending along one longitudinal side of the base. A collection of extension hair includes a plurality of supplemental strands secured to the base substantially opposite relative to the plurality of loops. As applied, the base and more specifically the plurality of loops are disposed in adjacent, substantially aligned relation to a hair part or seam formed in the natural hair of the wearer. A plurality of natural hair groupings are formed along one side of the seam and the plurality of loops are cooperatively disposed and dimensioned to facilitate passage of the hair groupings therethrough for attachment to one another thereby securing the base and the collection of extension hair in an intended position on the head of the wearer.