A novel directionally adaptive image resolution enhancement method is proposed. The method uses a multiple-direction wavelet transform, called directionlets, to efficiently extract edge information along different directions, not necessarily horizontal or vertical, from the low-resolution image. Then, the high-resolution image is synthesized using the extracted information to preserve sharpness of edges and texture. The novel algorithm provides the interpolated images at a higher resolution that are better than the images obtained by the state-of-the-art methods in terms of both numeric and visual quality.