Leash Reactivity: Why Is My Dog Aggressive When On Their Leash?

By Dr. Kaitlin Wurtz August 12, 2021

Walking your dog is a great bonding activity that has excellent health benefits for both you and your dog. Walks allow your dog to get mental and physical exercise as they sniff and explore their environment. Moreover, a walk outside can provide an opportunity for socialization with other people and other dogs that are out and about enjoying their day. Using a leash on a walk is an important component for walking your dog responsibly. Leashes help keep dogs out of trouble and running up to undesired animals, people, and places. But in some unfortunate cases, dogs develop fear or frustration while walking on a leash. Since this issue can be frustrating for some dog parents, we will explore how leash reactivity develops, how to prevent it, and how to manage it. This way you can get back to enjoying your favorite pastime with your dog without the issues.

What Is Leash Reactivity?

Leash reactivity is when dogs develop heightened responses to stimuli (most often other people or dogs) while being walked on a leash. Responses can range from excitement to aggression, and may include lunging, barking, or growling. Aggression is a normal and natural behavior that dogs perform and may be rooted in fear, territoriality, competition, or it may be a learned behavior and may be inadvertently reinforced (Mertens, 2002). While it is natural in household settings, aggression can become challenging to manage, may present a danger to others, or it may interfere with the human-animal bond (Haug, 2008). Leash reactivity is one of the most reported problems in shelter dogs reducing their adoption chances or increasing their likelihood that they are returned (Shih et al., 2020; Marston et al., 2005; Pirner and McGlone, 2016). Additionally, the forward lunging that many leash reactive dogs perform can have negative health implications such as damaging soft tissues in the neck and trachea and can contribute to increased eye pressure (Carter et al., 2020; Pauli et al., 2006).

What Are The Signs That Your Dog Is Leash Reactive?

The following are some common behavioral signs of a leash reactive dog. If your dog performs any of the following behaviors at the sight of another dog, person, or other stimuli such as squirrels or passing cars, then they may be considered leash reactive.

  • Staring
  • Freezing
  • Whining
  • Barking
  • Pulling
  • Lunging
  • Growling
  • Snapping or attempting to bite

Keep in mind that leash reactivity refers to the dog having a heightened response that may or may not include aggression. The strength of the response is directly related to the distance from the stimulus. For instance, the sight of a dog far off in the distance may only cause your dog to glance their direction but they remain calm and continue on their walk. A dog a block away may cause your dog to stop walking, stare, and freeze up. A close encounter with a dog, such as passing each other on the sidewalk may cause a strong reaction such as barking, lunging, and growling.

What Causes Leash Reactivity?

While factors such as genetics, negative early life experiences, and health issues can contribute to aggression (Horwitz, 2015), leash reactivity is almost always caused by dogs feeling frustrated or fearful and their response is their attempt to cope with the situation. Some dogs are raised being allowed to meet and greet every person or dog that walks by. Later in life when we try to ask these dogs to walk by without getting the chance to say “hi!”, they can get frustrated. This is further reinforced when we jerk the leash to encourage our dog to keep on walking. Over time, the dog’s frustration may manifest as lunging or barking to try to get to the other dog or person (Huag, 2008). Other times, dogs may be hesitant to meet other dogs or strangers while on a walk and may feel trapped or restricted by their leash and may try to distance themselves from others through the use of aggression. They may repeat this aggressive response as it has worked for them in the past. Unwanted encounters with others or fights with other dogs can further exacerbate leash reactivity problems (Horwitz, 2015).

Should You Punish Your Dog For Being Aggressive?

Punishment can increase feelings of stress and anxiety in dogs and can lead to increased displays of problematic behaviors (Hiby et al., 2004). The use of leash corrections, shock collars, and physical or verbal reprimands should always be avoided when working with dogs that are leash reactive, since these actions can further increase fear and anxiety. Punishment can also lead to dogs not signaling their discomfort which can lead to sudden unexpected biting as the dog’s last-ditch effort to stop a situation (Horwitz, 2015).

How To Prevent Leash Reactivity

There are steps that dog owners can take to help prevent their dog from becoming leash reactive. Research has shown that proper, early socialization up until 6 months of age can significantly reduce the changes of aggressive responses later in life (Appleby et al., 2002). By providing your young dog with positive, predictable meetings with other people and dogs they are more likely to grow up to be confident dogs. If you do introduce your dog to other dogs or people on walks while leashed, try to keep their emotional level low and controlled. You could have them sit before the greeting to help keep their excitability low and well mannered. If you notice your dog acting nervous or reluctant before a greeting, do not force them into an interaction. Some dogs are more extroverted or introverted than others, and some prefer the company of people over dogs and vice versa. Forcing your dog to interact when they do not want to could lead to your dog becoming leash reactive.

How Can You Fix Leash Reactivity?

If you think your dog is leash reactive, there are proven methods that can help make your walks together enjoyable again. The methods most recommended by respected dog trainers and behaviorists involve changing your dog’s underlying emotional state and teaching them better coping mechanisms for when they encounter overwhelming stimuli. Classical counter conditioning is a useful tool that can help your dog associate scary stimuli with something positive, such as cookies or praise, causing them to look forward to those positive interactions at the sight of the stimulus instead of reacting negatively (Horwitz, 2005). One game that can be played with your dog to change their emotional state and give them alternative coping mechanisms is discussed on Karen Pryor’s website and is called the “engage-disengage game” (Tong, 2014). This game consists of two major levels which are broken down into steps here:

  • Level 1 – Engage
    1. Gather your leashed dog, a clicker, and some high value treats or toys.
    2. Begin this exercise within eyesight of your dog’s trigger, but at a far enough distance from the trigger that your dog remains calm.
    3. Patiently wait for your dog to notice the trigger. As soon as they do, click the clicker.
    4. As soon as your dog turns their head back to you after noticing the click, give them a reward (treats or play time).
    5. If they are too into the trigger to turn back to you, then this is a sign that you need to move further away from the stimulus for this exercise.
    6. After your dog has successfully noticed the trigger and looked back at you for their treat 3 to 5 times, advance to level 2.
  • Level 2 – Disengage
    1. This time, after your dog notices the trigger, do not click. Instead wait 1 to 5 seconds for your dog to look back at you on their own. Go back to level 1 if your dog remains fixated on the trigger.
    2. As soon as your dog looks back at you, click and give them a reward.
    3. After 3 to 5 repetitions of Level 2 you may begin moving a few steps closer to the trigger
    4. Each time you advance closer, repeat the steps of Level 2
  • Each game of “engage-disengage” should only be played for about 5 minutes. Work slowly and never advance before your dog is ready (Bain, 2009). The goal is to prevent the dog from reacting and to teach them to look to you for a reward. Over time, your dog will start noticing triggers and feel happy/excited for the treat or play time they will get from you.

When training with a leash reactive dog, always ensure that you can humanely retain control of them at all times. Harnesses or head collars such as a gentle leader work great for this while preventing injury to your dog’s sensitive throat. Consider using a muzzle if you are concerned with your dog accidentally biting someone. If properly fitted, muzzles can be a great humane safety tool that can add peace of mind to your training practice!


Dogs that are leash reactive may have heightened reactions to other dogs or people on walks due to feelings of fear and frustration. The leash adds additional stress by making the dog feel trapped. In order to successfully reduce leash reactivity, you’ll need to increase the dog’s confidence. Never force them into unwanted social interactions and gradually teach them better ways to respond.

Works Cited

Appleby, D. L., John WS Bradshaw, and Rachel A. Casey. "Relationship between aggressive and avoidance behaviour by dogs and their experience in the first six months of life." Veterinary Record 150, no. 14 (2002): 434-438.

Bain, Melissa. "Aggression toward unfamiliar people and animals." In BSAVA manual of canine and feline behavioural medicine, pp. 211-222. BSAVA Library, 2009.

Carter, Anne, Donal McNally, and Amanda Roshier. "Canine collars: an investigation of collar type and the forces applied to a simulated neck model." Veterinary Record (2020).

Haug, Lore I. "Canine aggression toward unfamiliar people and dogs." Veterinary Clinics of North America: Small Animal Practice 38, no. 5 (2008): 1023-1041.

Hiby, E. F., N. J. Rooney, and J. W. S. Bradshaw. "Dog training methods: their use, effectiveness and interaction with behaviour and welfare." ANIMAL WELFARE-POTTERS BAR THEN WHEATHAMPSTEAD- 13, no. 1 (2004): 63-70.

Horwitz, D. F. "Classical Counter-Conditioning as a Treatment Modality for Dogs (Canis familiaris) Showing Aggression Toward Other Dogs on Walks." Current issues and research in veterinary behavioral medicine (2005): 207-210.

Horwitz, Debra F., and Veterinary Behavior Consultations. "How to help dogs that are aggressive during leash walking.” Today’s Veterinary Practice (2015).

Marston, Linda C., Pauleen C. Bennett, and Grahame J. Coleman. "Adopting shelter dogs: owner experiences of the first month post-adoption." Anthrozoös 18, no. 4 (2005): 358-378.

Mertens, P. A. "BSAVA Manual of canine and feline behavioural medicine." In Canine Aggression, pp. 195-215. BSAVA, Gloucester, 2002.

Pauli, Amy M., Ellison Bentley, Kathryn A. Diehl, and Paul E. Miller. "Effects of the application of neck pressure by a collar or harness on intraocular pressure in dogs." Journal of the American Animal Hospital Association 42, no. 3 (2006): 207-211.

Pirner, Glenna, and John McGlone. "Impact of androstenone on leash pulling and jumping up in dogs." Animals 6, no. 5 (2016): 34.

Shih, H. Y., M. B. A. Paterson, F. Georgiou, and C. J. C. Phillips. "Do Canine Behavioural Assessments and Characteristics Predict the Human-Dog Interaction When Walking on a Leash in a Shelter Setting? Animals 2021, 11, 26." (2020).

Tong, A. (2014, July 1). Reducing Leash Reactivity: The Engage-Disengage Game. Reducing Leash Reactivity: The Engage-Disengage Game | Karen Pryor Clicker Training.