Described is an electronic pet door for automatically granting a selected animal access to a through-way defined by the electronic pet door and denying a non-selected animal access to the through-way. The selected animal carries a transmitter. The electronic pet door includes a corresponding receiver and a frame that defines the through-way, which has a tapered contour. A flap, which has a tapered contour corresponding to the through-way, is disposed within the through-way and is capable of a locked position and an unlocked position. When in the locked position, the flap denies access to the through-way. When unlocked, the flap grants an animal access to the through-way. The flap is locked and unlocked by way of a locking mechanism that shifts the flap longitudinally between the less tapered and most tapered portions of the through-way. The locking mechanism shifts the flap in response to the receiver.