Short answer
Harnesses differ in where the lead clips on (back, chest or both), how they go on (over-head, step-in or clip-around) and the shape of the front. Whatever the type, Battersea says a good harness "should avoid pressure on your dog's neck and allow free shoulder movement", with a Y-shaped front1.
In this guide
- Harness or collar: which is better?For walking, especially a dog that pulls, a harness: the PDSA says "We recommend walking your dog on a harness if they pull - this will help prevent them from hurting their neck." But in the UK your dog still needs a collar with your name and address in public, with some exceptions, so most owners use both..
- Front-clip or back-clip harness for a dog that pulls?No study we've found compares front-clip and back-clip harnesses directly.
- Dog car harnesses and the lawRule 57 of the Highway Code says dogs in a vehicle should be "suitably restrained so they cannot distract you while you are driving or injure you, or themselves, if you stop quickly", and lists "A seat belt harness, pet carrier, dog cage or dog guard" as ways to do it.
- The best harness type for flat-faced breedsFor flat-faced breeds, the RSPCA, PDSA and Royal Kennel Club all advise walking on a harness rather than a collar, to keep pressure off the neck and airway.
Why a harness at all?
The PDSA says: "We recommend walking your dog on a harness if they pull - this will help prevent them from hurting their neck."2
For flat-faced breeds, the RSPCA, PDSA and Royal Kennel Club all advise a harness rather than a collar for walking3,4,5. In the UK your dog still needs a collar and ID tag in public, with some exceptions6, so most owners use both: the lead on the harness, the tag on the collar.
For the full comparison, read harness or collar: which is better?
What every good harness has in common
Battersea says: "A good harness should avoid pressure on your dog's neck and allow free shoulder movement. Look for a Y-shaped front for comfort."1
- No pressure on the neck. The front should sit low on the breastbone, not across the throat.
- Free shoulders. The straps should stay out of the way of the front legs as they swing forward.
- A Y-shaped front. Straps come down from either side of the neck and meet in the middle of the chest1.
- Nothing painful or restricting. The PDSA also says: "Don't use anything that is painful for your dog or restricts their movement (such as a choke collar)."2
Where the lead clips on
The biggest difference between harness types is where you attach the lead.
| Type | Lead attaches | Notes |
|---|---|---|
| Back-clip | A ring on the back, between the shoulder blades | The most common design. The lead pulls from above. |
| Front-clip | A ring on the chest | Some brands say a front clip helps redirect a dog that pulls7. |
| Dual-clip | Both a back ring and a chest ring | Lets you choose. Ruffwear's Front Range is one example7. |
Front-clip or back-clip?
Ruffwear describes its Front Range harness as having "an aluminum V-ring centered on the dog's back for everyday walks, and reinforced front clip at the dog's chest to redirect dogs that pull on leash"7. That is the brand's own description of its product.
We haven't found a study that compares front-clip and back-clip harnesses directly. A 2024 study by Johnson and Wynne walked 23 dogs on a martingale collar, a front-connection harness and two prong-style collars. Pulling was significantly lower on the front-connection harness (and on both prong collars) than on the martingale collar, with no significant difference among those three, and the authors found no clear evidence of poorer welfare on any of them. They caution against generalising from a small study8.
More in front-clip or back-clip harness for a dog that pulls?
How it goes on: over-head, step-in or clip-around
Battersea says: "Try different styles (over-head, step-in or clip-around) to see what your dog prefers."1 It adds: "Choose a clip-around harness if lifting legs is uncomfortable."1
- Over-head: a loop goes over the head, then the chest strap clips round. Quick once your dog is used to it.
- Step-in: your dog steps its front feet into two loops and you clip it over the back. Nothing goes over the head.
- Clip-around: wraps round and buckles shut, without going over the head or lifting the legs1.
Putting each one on
Step-by-step instructions are in how to put a dog harness on.
Front shape and shoulder movement
Battersea recommends a Y-shaped front for comfort1. Some harnesses have a strap straight across the chest instead, which can sit across the front of the shoulders.
A small 2019 study by Lafuente, Provis and Schmalz looked at 9 dogs walking and trotting in two harness designs. Both reduced how far the shoulder extended forward, and the harness described as "non-restrictive" reduced it slightly more9. With so few dogs, it's a reason to watch how your own dog moves, not a verdict on any design.
We suggest watching your dog walk and trot in any new harness. If its stride looks shorter than without the harness, adjust the fit or try a different design.
Switching harness types
Battersea says: "Switching harness types can help if your dog has negative associations with a previous harness or if they have already learned to pull strongly in certain equipment."1 If your dog dislikes its harness, or has learned to lean into it, a different style may help.
Car harnesses
Rule 57 of the Highway Code says: "When in a vehicle make sure dogs or other animals are suitably restrained so they cannot distract you while you are driving or injure you, or themselves, if you stop quickly. A seat belt harness, pet carrier, dog cage or dog guard are ways of restraining animals in cars."10
A walking harness and a car harness aren't necessarily the same thing. Read dog car harnesses and the law.
Flat-faced breeds
The RSPCA says: "Walk your dog on a harness rather than a collar and lead, to avoid putting pressure on their neck and help them breathe easier."3
For these breeds, keeping every strap off the throat matters most. Read the best harness type for flat-faced breeds.
What the research says
There isn't much research on harnesses and collars, and the studies we've found are small or use models. Here is what they found, with their limits.
- Collars and neck pressure (a model, not live dogs). A 2020 study by Carter, McNally and Roshier tested seven collars and a slip lead on a model of a dog's neck, not on live dogs. It found: "Collars exerted a pressure of between 83 kPa and 832 kPa", and "No single collar tested provided a pressure considered low enough to mitigate the risk of injury when pulling on the lead."11
- Pulling on a front-connection harness. A 2024 study by Johnson and Wynne walked 23 dogs on a martingale collar, a front-connection harness and two prong-style collars. Pulling was significantly lower on the front-connection harness (and on both prong collars) than on the martingale collar, with no significant difference among those three, and the authors found no clear evidence of poorer welfare on any of them. They caution against generalising from a small study8. The study didn't test a back-clip harness.
- Harnesses and shoulder movement. A small 2019 study by Lafuente, Provis and Schmalz looked at 9 dogs walking and trotting in two harness designs. Both reduced how far the shoulder extended forward, and the harness described as "non-restrictive" reduced it slightly more9. With so few dogs, it's a reason to watch how your own dog moves, not a verdict on any design.
Prong collars
We don't suggest prong collars. The RSPCA says: "Prong collars are designed to cause pain or discomfort to the animal to reduce or stop them from pulling on their lead," and "Research has shown that aversive training techniques, like prong collars, can cause pain and distress and can compromise dog welfare."12
Which type for which dog?
A quick guide to matching the type to your dog. The links go to the detail.
| Your dog | Type to consider |
|---|---|
| Pulls on the lead | A harness rather than a collar2; consider a front or dual clip (front-clip or back-clip?) |
| Flat-faced breed | A harness for walks3, Y-front sitting low (flat-faced breeds) |
| Finds lifting its legs uncomfortable | Clip-around1 |
| Dislikes things over its head | Step-in or clip-around |
| Slips out of harnesses | We suggest a design with an extra strap behind the ribs, fitted snugly (signs it's too big) |
| Puppy | Any type that fits now (when can a puppy wear a harness?) |
| Travels in the car | A harness the maker says is for car use (car harnesses and the law) |
Padding, materials and hardware
Beyond the type, a few details make a difference day to day. These are our own suggestions:
- Padding where it presses. Soft padding on the chest and behind the front legs spreads the load and is kinder on short-coated dogs.
- Smooth straps for long coats. Flat, smooth webbing is less likely to tangle curly or long coats.
- Strong rings and buckles. Check the lead rings and buckles are solid, and that buckles close with a firm click.
- Easy adjustment. Plenty of adjustment on each strap helps with coat changes and a growing puppy.
- Visibility. Reflective trim helps on dark evenings.
Sizing is by chest, whatever the type
Harness brands size by chest girth, which Ruffwear describes as "the widest part of your dog's chest just behind the front legs"13. Each brand cuts its sizes differently, so check your dog's measurement against the chart for the harness you choose. Our size finder does this for every brand we cover, and our breed harness guides show the sizes most adults of each breed need.
How to choose
- Measure your dog's chest and find its size in each brand: our size finder does this.
- Choose a design with a Y-shaped front that keeps pressure off the neck and leaves the shoulders free1.
- Pick the clip position. If your dog pulls, consider a design with a front clip or both clips (see above).
- Pick the style your dog is comfortable with: clip-around if lifting legs is uncomfortable1.
- For the car, check the maker says the harness is designed for car use.
- Fit it properly. Our guide to how a dog harness should fit covers every strap.
Common mistakes
- Choosing a harness that presses on the throat or sits across the shoulders.
- Using a harness that tightens painfully or restricts movement. The PDSA says not to use anything painful or restricting2.
- Leaving off the collar and ID tag in public6.
- Assuming any walking harness is suitable as a car restraint.
- Expecting a harness alone to stop pulling. It changes where the force goes; training is a separate job.
Breed harness guides
Every breed fits a harness a little differently. These guides cover the sizes in each brand, how to measure that breed, and the styles that suit it.
- Labrador Retriever harness sizeSizes by brand, measuring and fit
- French Bulldog harness sizeSizes by brand, measuring and fit
- Staffordshire Bull Terrier harness sizeSizes by brand, measuring and fit
- Siberian Husky harness sizeSizes by brand, measuring and fit
- Whippet harness sizeSizes by brand, measuring and fit
- Boxer harness sizeSizes by brand, measuring and fit
Find your dog's harness size All breeds
Questions
What type of harness is best for my dog?
One that avoids pressure on the neck and allows free shoulder movement, with a Y-shaped front1, in a style your dog is comfortable with, fitted properly.
Is a front-clip or back-clip harness better?
We haven't found a study comparing them directly. Ruffwear says its front clip is "to redirect dogs that pull on leash"7. A dual-clip harness lets you use either.
Is a harness better than a collar for a dog that pulls?
The PDSA recommends a harness if your dog pulls, to help prevent it hurting its neck2.
What is a clip-around harness?
One that wraps round your dog and buckles shut, without going over the head or lifting the legs. Battersea suggests one if lifting legs is uncomfortable1.
Does my dog still need a collar if it wears a harness?
In a public place, yes, with some exceptions: the Control of Dogs Order 1992 requires a collar with the owner's name and address6.
Can I use my walking harness in the car?
Check what the maker says about car use. The Highway Code lists a seat belt harness as one way to restrain a dog10.
Read next
- Harness or collar: which is better?For walking, especially a dog that pulls, a harness: the PDSA says "We recommend walking your dog on a harness if they pull - this will help prevent them from hurting their neck." But in the UK your dog still needs a collar with your name and address in public, with some exceptions, so most owners use both..
- Front-clip or back-clip harness for a dog that pulls?No study we've found compares front-clip and back-clip harnesses directly.
- Dog car harnesses and the lawRule 57 of the Highway Code says dogs in a vehicle should be "suitably restrained so they cannot distract you while you are driving or injure you, or themselves, if you stop quickly", and lists "A seat belt harness, pet carrier, dog cage or dog guard" as ways to do it.
- The best harness type for flat-faced breedsFor flat-faced breeds, the RSPCA, PDSA and Royal Kennel Club all advise walking on a harness rather than a collar, to keep pressure off the neck and airway.