How to Choose a Dog Harness

Key Guidance

Before buying anything, take two measurements: the neck base where it meets the shoulders, and the widest part of the chest just behind the front legs. Once you have a harness in hand, do a fit check — you should be able to slide roughly two fingers underneath any strap. That's the target zone: snug enough that your dog can't back out of it, loose enough that it won't chafe or restrict breathing.

A harness is generally the better everyday option — rather than a collar — for a number of dogs. Brachycephalic, or short-nosed, breeds such as Bulldogs, French Bulldogs, and Pugs often have a neck nearly as wide as their head, which makes it easy for them to slip a collar. Older dogs, dogs with neck pain, tracheal sensitivity, breathing difficulties, or heart disease also tend to do better in a harness, as do dogs that pull hard enough on leash to risk straining their throat or neck. Sighthounds, such as Greyhounds and Whippets, carry a related but distinct risk: because their head can be narrower than their neck, a standard collar is a genuine escape risk for the breed type, independent of any pulling behavior.

Harness design matters too. Front-clip harnesses attach at the chest and give you leverage to redirect a dog that pulls, turning them back toward you rather than letting them tow you forward. Back-clip harnesses, which sit near the shoulder blades, work well for calm, already-mannered dogs but offer less control over pulling. Dual-clip designs let you start front-clip while training loose-leash walking and move toward back-clip use as the pulling habit improves.

It's worth being clear-eyed about one more distinction: an everyday walking harness and a vehicle-restraint harness are not the same product, even when they look similar. Independent crash testing has found that most harnesses marketed for car use did not keep a test dog secured on the seat during a simulated crash, and that "extension tether" or zipline-style attachments actually increased injury risk in testing. If a harness will double as car restraint, that's a separate question from whether it fits well for a walk.

What to Consider

Start with purpose: are you buying primarily for walks, for vehicle travel, or both? A harness that's comfortable on a walk has not necessarily been evaluated for crash safety, so if car restraint matters, look specifically for independent crash-test data rather than assuming a "car harness" label settles the question. From there, let your dog's body shape and any known risk factors guide the collar-vs-harness decision — brachycephalic anatomy, a narrow head-to-neck ratio, or an existing neck, back, or breathing condition all point toward a harness. If your dog pulls consistently, a front-clip or dual-clip design can help, but it works best alongside leash training rather than as a replacement for it. Finally, plan to re-check fit periodically, especially for a growing puppy or after any noticeable weight change, since a harness that fit well six months ago may no longer be right.

Cautions or Common Mistakes

• A too-loose harness can be backed out of, particularly by sighthounds or frightened dogs; a too-tight one can chafe, restrict shoulder movement, or add discomfort in hot weather.
• Assuming any product labeled "car harness" is crash-safe — independent testing found most are not, and cracking a window or simply holding a dog in a moving car is not a substitute for real restraint.
• Letting a dog ride with its head out an open window — airborne debris can injure the eyes, ears, nose, and mouth.