Glossary

Dog door

A flap or panel set in a door or wall that lets a dog go in and out of the house on its own.

Also called: pet door, doggy door, dog flap, cat flap, electronic dog door, doggie door

A dog door is a hinged flap fitted into a door, a wall or a sliding glass panel that lets a dog come and go. Basic models are plastic or rubber flaps, and others have a lock panel, insulation for weather or an electronic mechanism that opens only for a dog wearing a special tag or chip.

To size one, measure the dog's height at the withers and its width at the widest point, and check the maker's chart. Follow the maker's guidance on how high the bottom edge should sit. Choose a large size for a growing puppy, and note that dog doors may also let in wildlife or small intruders, which is why locks and electronic types exist.

A dog door only works if the yard is fully fenced and safe. Check that the lease, landlord or homeowners association allow one before cutting a hole.

Last reviewed November 8, 2026

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Related terms

Exercise pen A freestanding set of hinged panels that forms a portable fenced area for a dog, bigger than a crate and easy to fold away. GPS dog tracker A collar-mounted device that uses satellite positioning and a cellular connection to show your dog's location on a phone, usually for a monthly fee. Withers The ridge between a dog's shoulder blades at the base of the neck, the standard point from which a dog's height is measured. Dog crate A box or cage that provides a dog with a safe, enclosed space at home or in a car; it should be large enough to stand, turn and lie down in.