This chapter surveys the contributions of projective geometry to computer vision. Projective geometry deals elegantly with the general case of perspective projection and therefore provides interesting understanding of the geometric aspect of image formation. It also provides useful tools like perspective invariants. First the major definitions and results of this geometry are presented. Applications are then provided for several domains of 3-D computer vision, including location of the viewer for uncalibrated cameras, properties of epipolar lines in stereovision and object recognition.