A potting training device for preventing a potty-training child's urine stream from passing through the opening formed between the toilet seat and the toilet bowl. The device is made of a flexible, water-resistant, preferably non-porous sheet material, having a folding seam separating a urine-deflecting surface and a plurality of attachment tabs. An adhesive material is applied to the surface of each attachment tab and attaches the attachment tabs to the underside of the toilet seat. The sheet material, in its unattached flat configuration, is manipulated into a curved configuration that matches the curvature of the toilet seat, and is attached thereto. The potty training device is also not visible to the observer unless the toilet seat is lifted up, in a vertical position or viewed from a position to the rear of the attachment point when the toilet seat is down.