Houndstooth, hounds tooth check or hound's tooth, also known as dogstooth, dogtooth, dog's tooth,, is a duotone textile pattern characterized by a tessellation of light and dark solid checks alternating with light-and-dark diagonally-striped checks—similar in pattern to gingham plaid but with diagonally-striped squares in place of gingham's blended-tone squares—traditionally in black and white, although other contrasting colour combinations may be used.

Check is a pattern of modified stripes consisting of crossed horizontal and vertical lines which form squares. The pattern typically contains two colours where a single checker is surrounded on all four sides by a checker of a different colour.