A weep hole screen and method for installing the same in the exterior wall of a masonry building in order to prevent small animals such as insects and rodents from entering the building through the weep hole. A weep hole screen in accordance with the present invention preferably comprises a rectangular mesh screen with an angle bracket attached to each end. The weep hole screen is sized such that the angle brackets sandwich the bricks that form the weep hole, preferably on the interior faces of the bricks. The interfaces between the weep hole screen and the bricks are preferably sealed with mortar or another suitable sealant. The weep hole screen may be installed easily during original construction of the wall without the need for any mechanical fasteners.