Massachusetts has one of the most victim-friendly dog bite laws in the country. Under G.L. c. 140, § 155, a dog’s owner or keeper is strictly liable for any damage the dog does to a person or their property. You do not have to prove the owner was careless, and you do not have to prove the dog ever bit anyone before. This guide explains how the statute works, who can be held liable, what the exceptions are, and what compensation victims can recover.
Strict Liability in 60 Seconds: There Is No “One Free Bite” in Massachusetts
Many states follow a common law “one bite rule,” under which an owner is liable only if they knew or should have known the dog was dangerous, usually because it had bitten someone before. Massachusetts abolished that approach by statute. Under G.L. c. 140, § 155, liability attaches the first time a dog injures someone, regardless of the animal’s history and regardless of how carefully the owner handled it.
The statute provides that if any dog “shall do any damage to either the body or property of any person, the owner or keeper” shall be liable for that damage. If the owner or keeper is a minor, the minor’s parent or guardian is liable instead. Three things stand out:
- No negligence required. The victim does not need to show the owner did anything wrong. A leashed dog on a fenced property can still create liability if it injures someone.
- No prior viciousness required. The dog’s clean history is not a defense.
- “Damage” is broad. The statute covers damage to the body or property of any person, not just bite wounds. Knockdowns, scratches, and chase-related injuries all qualify.
The Statute’s Exact Exceptions
Strict liability is not absolute liability. Section 155 excuses the owner or keeper when the injured person, at the time the damage was sustained:
- Was committing a trespass or other tort. Someone who breaks into a fenced yard or enters a home without permission generally cannot recover under the statute. The trespass must be occurring at the time of the injury.
- Was teasing, tormenting, or abusing the dog. Provoking the animal, poking it, pulling its tail, striking it, or deliberately agitating it, forfeits the statutory claim.
These are the only exceptions. Note what is missing: there is no exception for “the dog was startled,” “the victim should have known better,” or “the dog was protecting its territory” against a lawful visitor. Mail carriers, delivery drivers, invited guests, and people on public sidewalks are all protected. Because the exceptions function like affirmative defenses, disputes over whether the victim was trespassing or provoking the dog are usually the central battleground in these cases, and the statutory scheme, not ordinary comparative negligence rules, is the starting point.
The Under-7 Child Presumption
Children are the most frequent victims of serious dog attacks, and the statute gives them special protection. Section 155 states that if the injured minor is under seven years old at the time of the injury, “it shall be presumed that such minor was not committing a trespass or other tort, or teasing, tormenting or abusing such dog, and the burden of proof thereof shall be upon the defendant.”
In practical terms, an owner who wants to argue that a five-year-old provoked the dog must prove it. The child’s family does not have to disprove provocation. This burden shift is significant because young children often cannot give a reliable account of what happened, and juries are understandably reluctant to blame a small child for a dog’s attack. For children seven and older, the exceptions apply normally, though age and maturity still shape how a jury evaluates claims of teasing or trespass.
Who Is Liable: Owner, Keeper, and Sometimes a Landlord
The statute reaches the dog’s owner or keeper. The owner is usually easy to identify. A “keeper” is someone who harbors the dog and exercises a degree of care, custody, or control over it, for example, a family member who houses the dog, a dog sitter, or a boyfriend or girlfriend who keeps a partner’s dog at their apartment. Whether someone is a keeper is a fact question, and more than one person can be responsible for the same dog.
Landlords are generally not keepers of a tenant’s dog. The Appeals Court held in Brown v. Bolduc, 29 Mass. App. Ct. 909 (1990), that a landlord does not become a keeper merely by renting premises to a tenant who owns a dog, even where the landlord permits the dog on the property. Simply collecting rent from a dog owner does not create strict liability.
That is not the end of the landlord question, though. In Nutt v. Florio, 75 Mass. App. Ct. 482 (2009), the Appeals Court allowed a common law negligence claim to proceed against a landlord whose tenant’s pit bull injured a child. While the landlord was not a keeper under § 155, a landlord who knows a dangerous dog is being kept on the property and retains control over the premises can owe a duty to protect others from it. In practice, that means investigating what the landlord knew: prior complaints, animal control reports, warnings from neighbors, and lease provisions about pets. Landlord claims matter most when the dog’s owner is uninsured, because the landlord’s premises liability coverage may be the only real source of recovery. Our Massachusetts premises liability guide covers how these property-based claims work.
Beyond Bites: Knockdowns, Chases, and Scratches Count
Section 155 is not a “dog bite” statute in the narrow sense. It covers any damage a dog does “to either the body or property of any person.” Massachusetts courts have applied it to injuries with no bite at all, including:
- A large dog jumping on someone and knocking them to the ground, causing fractures or head injuries
- A dog chasing a bicyclist or motorcyclist who crashes trying to avoid it
- A dog running into a pedestrian or runner and causing a fall
- Deep scratches and torn clothing or damaged property
Elderly knockdown victims often suffer hip and wrist fractures more serious, and more expensive, than many bite wounds. If a dog caused your injury in any physical sense, the statute likely applies.
Insurance: Where the Money Actually Comes From
Dog owners rarely pay judgments out of pocket. In most cases, compensation comes from the owner’s homeowner’s or renter’s insurance, which typically includes personal liability coverage of $100,000 to $500,000. That coverage usually follows the owner wherever the incident happens, at home, at a park, or on a sidewalk.
Two realities complicate the picture. First, many insurers now use breed exclusions or refuse to renew policies for households with breeds they consider high risk, such as pit bull types, Rottweilers, and German Shepherds. If the owner’s policy excludes the dog, the claim may have to target the owner’s personal assets or a third party such as a landlord. Second, renters are far less likely to carry liability insurance at all. Identifying every potentially responsible party, and every applicable policy, early in the case is often the difference between a recoverable claim and a paper judgment.
The Dangerous Dog Hearing: A Separate Track
Compensation is handled through an insurance claim or civil lawsuit. Public safety is handled separately under G.L. c. 140, § 157. Any person may file a written complaint with the local hearing authority (typically the selectboard, city council designee, or police chief) alleging that a dog is a nuisance dog or a dangerous dog. The authority investigates and holds a public hearing.
If the dog is found dangerous, the hearing authority can order remedies including secure confinement on the owner’s premises, muzzling and restraint off premises, proof of liability insurance of at least $100,000, microchipping or other identification, spaying or neutering, or, in the most serious cases, humane euthanasia. Notably, the statute forbids deeming a dog dangerous based solely on its breed, and Massachusetts municipalities may not enact breed-specific regulations. A § 157 finding does not pay your medical bills, but the hearing record, witness statements, and any prior complaints can become powerful evidence in the civil case.
Separately, Massachusetts public health rules require a dog that bites a person to be quarantined for a 10-day rabies observation period, usually at the owner’s home, and bite wounds treated by medical providers are reported to local animal control. That report creates an official record identifying the dog and its owner, which is why reporting every bite matters.
What Victims Can Recover
Damages in a Massachusetts dog bite case follow ordinary personal injury principles:
- Medical expenses, past and future, including emergency care, wound repair, infection treatment, and physical therapy
- Scarring and disfigurement. Facial bites, especially in children, often require staged plastic surgery, and revision procedures may need to wait until the child stops growing. Future surgical costs belong in the claim, supported by a plastic surgeon’s opinion.
- Psychological injury. Children frequently develop lasting fear of dogs, nightmares, and symptoms of post-traumatic stress. Treatment costs and the emotional harm itself are compensable.
- Lost wages and diminished earning capacity for working adults
- Pain and suffering, including the permanence and visibility of scars
- Property damage, from torn clothing to a wrecked bicycle
Claims for minors involve an extra step: Massachusetts settlements for children generally require court approval, and settlement funds are protected until the child reaches adulthood.
Steps to Take After a Dog Bite
- Get medical care immediately. Dog bites carry a high infection risk, and prompt treatment also documents the injury.
- Identify the dog and its owner. Get the owner’s name, address, and, if possible, proof of rabies vaccination.
- Report the bite to animal control in the city or town where it happened. This triggers the quarantine and creates an official record.
- Photograph everything: the wounds on the day of the bite and as they heal, torn clothing, the scene, and the dog if it can be done safely.
- Collect witness names and contact information.
- Do not give a recorded statement to the owner’s insurer before understanding your rights, and do not accept an early settlement while scarring is still maturing.
The Deadline to Sue
Massachusetts applies its standard three-year personal injury statute of limitations, G.L. c. 260, § 2A, to dog bite claims. The clock generally runs from the date of the attack. For minors, the period is tolled until the child turns 18, but waiting is rarely wise: witnesses move, records disappear, and insurance evidence goes stale. See our full guide to the Massachusetts personal injury statute of limitations for tolling rules and exceptions.
Frequently Asked Questions
Does Massachusetts have a one-bite rule?
No. Massachusetts is a strict liability state under G.L. c. 140, § 155. The owner or keeper is liable for the dog’s first attack, without proof of negligence or prior aggression, unless the victim was trespassing, committing another tort, or teasing, tormenting, or abusing the dog.
What if the dog never bit anyone before?
It does not matter for liability. The statute imposes liability regardless of the dog’s history or the owner’s knowledge of any dangerous tendencies. A gentle dog with no prior incidents still creates full liability the first time it injures someone.
Can I claim if a dog knocked me off my bike?
Yes. The statute covers any damage a dog does to a person’s body or property, not just bites. Knockdowns, chases that cause crashes, and scratch injuries are all covered, along with the damage to the bicycle itself.
Is the landlord liable for a tenant’s dog?
Not under the strict liability statute merely for renting to a dog owner; Massachusetts courts have held a landlord is not a “keeper” on that basis alone. But a landlord who knew a dangerous dog was on the property may face a separate negligence claim, as the Appeals Court recognized in Nutt v. Florio (2009).
Does homeowner’s insurance cover dog bites?
Usually yes, through the personal liability portion of a homeowner’s or renter’s policy, commonly $100,000 to $500,000 in coverage. Watch for breed exclusions: some policies exclude specific breeds, which can leave the owner personally exposed and shift attention to other responsible parties.
What is the deadline to sue for a dog bite in Massachusetts?
Three years from the date of the injury under G.L. c. 260, § 2A. For a child victim, the deadline is paused until the child turns 18, though claims are stronger when investigated promptly.
This article is for general informational purposes and is not legal advice. Dog bite cases turn on their specific facts. If you or your child was injured by a dog in Massachusetts, speak with a personal injury attorney promptly.