Why does my dog bark at other dogs on walks?

You’re walking your dog, coffee in one hand, leash in the other. Then it happens: Your dog spots another dog, stiffens, fixates, and erupts into barking. But when you take that same dog to an off-leash park, they’re playful and friendly. What’s going on?

The reason dogs bark at other dogs on walks is deeply rooted in emotion: The leash changes how they feel and how they communicate.

A leash removes your dog’s ability to choose. They can’t retreat when uncomfortable or approach when curious. That loss of control is stressful, and stress changes behavior, causing your dog to bark at other dogs while on a leash. Research shows that restraint amplifies frustration and fear responses (Beerda et al., 1998; Deldalle & Gaunet, 2014). When that stress builds with no way to release it, the result is often barking, lunging, or growling.

Many dog owners think their dog is barking to protect them. While that’s a comforting thought, most barking at other dogs is rooted in one of the following two emotions: 

• Fear: “That other dog might be dangerous.” Barking and lunging help the fearful dog create distance and feel safer. It’s self-protection disguised as aggression

• Frustration: “I want to say hi, but I can’t get there.” The leash blocks their movement, and energy turns into barking. Over time, excitement turns into irritation, then into a conditioned reaction at the mere sight of another dog.

Both feelings can look the same from the outside: tense muscles, direct eye contact, high-pitched or rapid barking. But they stem from very different experiences. In either case, the leash transforms normal canine communication into something that looks explosive.

When your dog barks and the other dog leaves, your dog feels relief. That relief reinforces the behavior -- it worked (Blackwell et al., 2012). Over time, the sight of another dog automatically triggers arousal. The amygdala, which controls emotional reactions, fires faster than conscious thought, while inhibitory control from the frontal cortex weakens (Berns et al., 2016; Gobbo & Šemrov, 2022). The more it fires, the quicker the reaction next time. What starts as one bad moment becomes a habit loop.

The most effective long-term approach is counterconditioning—teaching your dog that other dogs predict good things, not bad ones. If your dog fixates on other dogs, start by teaching a calm focus behavior at a distance where they can still think. Teach them a cue to look at you, then pair that cue with other dogs at a safe distance. Say the cue once; when they look at you, immediately reward. This builds an alternate habit: see dog → look at you → good things happen. Over time, you can pair the appearance of another dog with positive associations, like treats, play, or praise, so the trigger predicts safety instead of threat.

This builds a calm habit of focus and rewires their emotional response. With consistency, the barking fades because the underlying emotion changes.

Take our quick quiz to see where your dog falls on the reactivity scale (mild, moderate, or high) and get personalized strategies for moving forward.

Beerda, B., Schilder, M.B.H., van Hooff, J.A.R.A.M., de Vries, H.W., & Mol, J.A. (1998). Behavioral, saliva cortisol and heart rate responses to different types of stimuli in dogs. Applied Animal Behaviour Science, 58(3-4), 365–381. https://doi.org/10.1016/S0168-1591(97)00145-7

Berns, G.S., Brooks, A.M., Spivak, M. (2016). Functional MRI in awake dogs reveals human-like brain responses to hand signals. PLoS One 7(5), e38027 https://doi.org/10.1371/journal.pone.0038027

Blackwell, E.J., Twells, C., Seawright, A., & Casey, R.A. (2008). The relationship between training methods and the occurrence of behavior problems, as reported by owners, in a population of domestic dogs. Journal of Veterinary Behavior, 3(5), 207–217. https://doi.org/10.1016/j.jveb.2007.10.008

Deldalle, S., & Gaunet, F. (2014). Effects of 2 training methods on stress-related behaviors of the dog (Canis familiaris) and on the dog–owner relationship. Journal of Veterinary Behavior, 9(2), 58–65. https://doi.org/10.1016/j.jveb.2013.11.004

Gobbo, E., & Šemrov, M. Z. (2022). Inhibitory control in aggressive dogs: The role of self-control and cognitive flexibility. Frontiers in Veterinary Science 9. https://www.frontiersin.org/articles/10.3389/fvets.2022.869068/full 

Author Bio

Shawna Baskette is a Canadian-born dog behavior educator with over 20 years of professional research experience and a specialty focus on reactivity. She studies peer-reviewed canine behavior literature, translates evidence into practical steps, and founded The Dog Library and Reactive Dog Reset to help dogs and owners reach calmer lives together.

If you think your dog is experiencing pain, and barks at other dogs while on walks, then your next read should be Is it Reactivity or Pain? How Discomfort Impacts Behavior.