The purpose of the dog guard is to shut off a space in a vehicle, usually the boot space and the back seat area in car's that have rear seats that fold down, which functions to contain any dogs that may be in the car when travelling.

Dog guards come in a variety of styles and shapes dependent on the make, model and often year of car. Dog guards should be sturdy and are usually made of metal or strong plastics, often a mesh construction allowing the driver and passengers travelling in the car to see their pet/s and vice versa. Most dog guards can be fitted into a vehicle quickly and with ease. Fastenings and fittings vary across models but often the dog guard can be fixed into the vehicle with the use of straps and velcro and attached to the headrest stalks.  Some models, however, will require a little more time and effort and may require permanent fixtures to be bolted in.

The dog guard is a safety feature which ensures that pets travelling in the vehicle can't jump into other areas and potentially distract the driver or cause an obstruction. Using a dog guard in a car when travelling with pets also ensures the driver is acting responsibly and safely and adhering to the Highway Code, which stipulates pets should not cause a distraction to the driver when driving. The dog guards also help to keep pets safe, in one area of the car, which can be comforting to an animal in terms of familiarity and security. Another benefit of using a dog guard in a vehicle is that it keeps any hairs, muddy paws and dirt contained within the boot area which helps to keep the rest of the car's interior clean.