Large white dog lunging while on leash.

Why is My Normally Nice Dog So Reactive When on a Leash?

Last updated on March 26th, 2023 at 07:03 pm

Does your perfectly sweet dog turn into your worst nightmare when you take him for walks on a leash? Does he suddenly try to rip your arm off and bark at other dogs or drag you off as he chases a squirrel or cat? You may feel perplexed at this behavior, since your dog is otherwise a very nice, well behaved dog. But get him on a leash, and he suddenly turns into this viscous beast that requires all of your attention and strength to control. What is going on?

Leash aggression or reactivity has many causes. Your dog is not a bad dog. He is simply acting on his instincts or he may be fearful about being on a leash and feels less able to protect himself and you. Understanding why your dog reacts so strongly to other dogs or critters while on leash, may help you better manage and deal with him during your daily walks.

What Does It Mean to Say a Dog is Leash Reactive?

A dog who is leash reactive will pull hard at his leash or lunge especially when approached by another dog or animal. He may also bark, bare his teeth, or growl as another dog or person approaches. Despite some of the best dog harnesses or collars, you may struggle to regain control once your dog is in a reactive mode while on leash.

I frequently take my dogs to the dog park and doggie day care. They love to run and play with other dogs, and so far, they have not had any fights or altercations with other dogs. So, I am always amazed how different my dogs are when walking on leash. Some dogs just irritate them for some reason, and they will growl or bark or pull hard at the leash. During one of our walks at the park, an energetic young dog charged my dog Charlotte from the rear. She immediately whirled around and started to fight with the dog. Fortunately, I was able to get the attention of the dog’s owner, and we were able to quickly separate then. Clearly, Charlotte felt the need to defend herself, and did not like being surprised.

A dog who is leash reactive may also cower, shake, whine, or lower his head and snarl if approached by another dog. Your dog may duck his tail or start panting heavily if he becomes really frightened. Interestingly, this same behavior may not not occur when he is off leash.

Causes of Reactivity While on Leash

So, what is it about the leash that causes a dog to react so strongly?

Walking on a leash can be stressful for a dog. It restricts his movements and natural tendencies to side-step or move away from something that frightens him. It may also be a source of frustration to be so tightly controlled and not allowed to run or move freely in the direction he is most interested in.

If a dog has ever been rushed or even attacked by another dog while on leash, his reactivity while on leash will only increase. He will become more guarded. His owner can add to his fear by quickly moving him away from other dogs, and giving off signals that other dogs and people are threats. In fact, this can sometimes be the cause of leash aggression.

More importantly, however, meeting another dog while on a leash is simply not natural for dogs. Meeting head-on, eyeball to eyeball, is considered aggressive in the dog world and perhaps threatening. But it is okay to sniff another dog’s butt or come up to them sideways. This is actually the preferred way that dogs like to meet! Sniffing another dog’s butt is a dog’s way of saying “Hello”!

So, when dogs are forced to meet head-on, this can be extremely intimidating.

Does a Reactive Dog Mean You Have an Aggressive Dog?

“Your dog is not bad. To determine if your dog is displaying threatening behavior, we need to look at several factors.

Sherry Clark, Seasoned Dog Trainer and owner of

Most dogs are not naturally aggressive. And, leash aggressiveness is specific to that situation and not the same as generalized aggression.

A dog who is overly reactive while on leash, may be afraid of something and is trying to protect himself or his owner. When a dog is tethered to a leash, dogs are restricted and more vulnerable. As a result, they may display threatening behavior as a warning to other dogs.

According to Sherry Clark, seasoned dog trainer and owner of, “Your dog is not bad. To determine if your dog is displaying threatening behavior, we need to look at several factors. Aggression (threatening behavior) can look like: Growling, snapping, lunging, barking, nipping, biting. You’ll be more successful if you start training when you think, ‘Was he just being aggressive?’ You’ll be less successful if you start training as a last resort.”

I have worked extensively with Sherry to help manage some of my dog’s impulsive tendencies. Fortunately for me Sherry is local, and we have been able to meet in person to do physical training like getting my dogs to heel and come. During Covid, Sherry was available by phone, and now offers remote training sessions for anyone in the USA.

She helped a lot with my dogs who were strenuous leash pullers. I could not walk to the park without getting my arm yanked off! They also had a tendency to run out open doors and bark excessively. It has been a lot of work, but we are making progress. We all get along a lot better than before the training. Sherry has always stressed that kindness and respect are key to raising and training dogs. Just like humans, dogs respond much better to positive reinforcement.

Of course, aggressive dogs do exist. We have all seen them. It is terrifying to encounter a dog who is baring his teeth, lunging, and barking ferociously. But my guess is that in most cases, aggressive behavior usually stems from intentional training by an owner who wants an attack dog for protection. And, too often, it is also due to abusive handling. But again, the behavior is most likely fear based and reactive as opposed to a natural tendency.

How To Manage Your Dog on a Leash

“Training, training, training! Trainers and vets often repeat this mantra. Training helps with just about all behavioral issues. This is especially true of walking your dog on a leash. A wild horse who has never been ridden first learns to get used to the saddle. Next, he will learn how to walk around a corral on que. Ultimately, a horse’s wilder instincts will be calmed and he may allow someone to ride him. Eventually, your dog will get used to wearing a collar and having a leash attached to him as part of his normal routine. This should start at the puppy age and continue throughout his lifetime.

Training will help a dog learn to think first and not just react impulsively to outside stimulus. Training also reminds your dog to listen to you and he will associate commands with positive rewards. All dogs benefit from basic obedience classes. This is true even if the classes do not specifically address problematic behavior. So start with a good obedience class. Then continue to work with a trainer to deal with the specific problem of leash reactivity.

Loose leash walking or teaching your dog to heel are very helpful. Loose leash walking involves teaching your dog to walk just a bit ahead of you or on your side. You will want him to learn to do this without putting tension on the leash. Dogs can learn to walk easily on a leash through the use of verbal and treat awards. You can also just stop every time your dog pulls. Eventually, he will learn that when he pulls, he gets the opposite of what he wants! See my post about what it might be like at the other end of the leash.

Teaching a dog to heel is more precise. It involves more of a march with your dog right at your side. This is a bit more work. However, you can easily train your dog by walking around with your dog close to your leg. Then you can dole out treats as he stays close. Use bits of hotdogs or cheese as enticements.

Body and head halters can be very helpful as you train your dog. Attaching a leash to a collar on a reactive dog is putting your dog’s neck at risk. It will also be hard on your shoulder and arm. There are a lot of good halters on the market which are very humane. They can be very effective and deter your dog from pulling or lunging. I have found that the Gentle Lead works best for my two dogs. I adopted them when they were older, so training has been a challenge. But these head halters have been life savers! See my recommended products equipment page to get a little more information about this halter.

It may take some work on your part, but ultimately, you and your dog will be much happier. With training, understanding, and good communication, your walks and outings will be so much more enjoyable. Additionally, training and walking together provide a great way for you and your dog to bond while getting some healthy exercise.

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