Massachusetts dog bite law puts the owner or keeper of the dog on the hook for injuries and property damage the dog causes, without requiring the victim to prove the owner knew the dog was aggressive. Under Chapter 140, Section 155 of the General Laws, you only have to show the injury happened and that you were not trespassing, provoking the dog, or committing another wrongful act at the time.1General Court of Massachusetts. Massachusetts General Laws Chapter 140 Section 155 That makes Massachusetts one of the more victim-friendly states for bite claims, though the same statute gives owners three complete defenses when the victim’s own conduct caused the incident.
Strict Liability Under Section 155
Section 155 makes the owner or keeper of a dog liable for any damage the dog causes to a person’s body or property. Massachusetts does not follow the “one-bite rule” used in some other states, so there is no need to prove the owner had reason to know the dog was dangerous. The dog can have a spotless history and the owner is still liable if it bites someone who was lawfully present.
The Massachusetts Appeals Court reinforced this in Irwin v. Degtiarov (2014), noting that the statute eliminates any need to prove the owner “knew of the dangerous character and habits of his dog.”2Justia. John Irwin vs. Arkady Degtiarov and Another In a one-bite-rule state, a case can turn entirely on whether the owner had prior warning. In Massachusetts, that question is off the table.
Who Counts as an Owner or Keeper
Liability is not limited to the person whose name is on the license. Section 155 reaches the “owner or keeper” of the dog, and a keeper is anyone who exercises care, custody, or control over the animal.1General Court of Massachusetts. Massachusetts General Laws Chapter 140 Section 155 A weekend dog-sitter, a family member housing the animal temporarily, or anyone else with day-to-day responsibility can qualify.
A landlord who simply rents to a tenant with a dog is generally not liable. But a landlord who actively harbors or exercises control over a tenant’s dog could be treated as a keeper. If the owner or keeper is a minor, liability shifts to the minor’s parent or guardian.
The Three Defenses
Section 155 gives an owner or keeper three complete defenses. If, at the time of the injury, the victim was doing any one of the following, the claim fails:
- Trespassing on the property where the bite occurred
- Committing another tort or wrongful act
- Teasing, tormenting, or abusing the dog
These are all-or-nothing bars to recovery, not partial reductions. Provocation is the defense that comes up most often. Casual interaction, like petting the dog, does not count. The conduct has to actually rise to teasing, tormenting, or abusing the animal.
Comparative Negligence
Outside those three statutory defenses, Massachusetts still applies modified comparative negligence under Chapter 231, Section 85.3General Court of Massachusetts. Massachusetts General Laws Chapter 231 Section 85 A victim’s damages are reduced by their percentage of fault, and a victim more than 50% at fault recovers nothing. So a victim who is 30% responsible for the incident would see their award cut by 30%, while one found 51% at fault collects zero. Careless conduct that falls short of “tormenting” the dog, like ignoring clear warning signs, can still reduce a recovery under this rule.
Special Protection for Children Under Seven
When the bite victim is a child under seven, the statute presumes the child was not trespassing, provoking the dog, or committing another wrongful act. The burden shifts to the owner or keeper to prove otherwise, and that is a hard argument to win. Convincing a factfinder that a five-year-old was teasing or tormenting a dog is difficult, so cases involving young children rarely fail on those defenses.
The same presumption applies in dangerous dog proceedings under Section 157: if the person attacked was under seven, the hearing authority presumes the child was not provoking, trespassing, or committing a crime.4General Court of Massachusetts. Massachusetts General Laws Chapter 140 Section 157
What You Can Recover
A successful claim under Section 155 can recover economic damages (medical bills, surgery, rehabilitation, lost wages, and property damage) and non-economic damages (pain and suffering, emotional distress, scarring, and loss of enjoyment of life). For bites that leave permanent scarring or nerve damage, the non-economic component often exceeds the medical bills.
Punitive damages are not available in a standard Massachusetts personal injury case, and that includes most dog bite claims. The narrow exception is wrongful death: if an attack kills someone and the owner’s conduct was malicious, willful, wanton, reckless, or grossly negligent, the estate can seek punitive damages of at least $5,000 under the wrongful death statute.5General Court of Massachusetts. Massachusetts General Laws Chapter 229 Section 2
Treble Damages for Previously Declared Dangerous Dogs
When a dog that has already been officially declared dangerous injures someone again, Section 159 makes the owner or keeper liable for three times the actual damages sustained.6General Court of Massachusetts. Massachusetts General Laws Chapter 140 Section 159 The multiplier applies automatically once those conditions are met and is the closest thing to punitive damages in a non-fatal Massachusetts dog bite case.
Reporting the Bite and the 10-Day Quarantine
Healthcare providers must report a dog bite to the Animal Inspector in the city or town where it happened within 24 hours.7Massachusetts Department of Public Health. Information About Reporting Animal Bites The reporting obligation applies whether or not the dog was vaccinated. Once the bite is reported, the dog is placed under a 10-day quarantine so the Animal Inspector can confirm the dog is healthy and rule out rabies transmission. The quarantine also applies regardless of vaccination status.
If you are the victim, getting prompt medical treatment sets that reporting process in motion and creates the paper trail you will need later. Medical records, the animal control report, and any photos of the injury are the backbone of a claim.
Three Years to File
You have three years from the date of the bite to file a personal injury lawsuit in Massachusetts, under the general personal injury statute of limitations in Chapter 260, Section 2A. Missing this deadline almost always ends the claim, no matter how strong the underlying facts are.
Three years can shrink quickly. Serious bites often require multiple surgeries and long recovery, and many victims delay talking to a lawyer until treatment winds down. Waiting until the two-and-a-half-year mark can leave too little time to collect records, identify the correct owner or keeper, and try to settle before you are forced to file suit.
Where the Money Actually Comes From: Insurance
In practice, most Massachusetts dog bite recoveries are paid by homeowners’ or renters’ insurance. The dog’s owner files a claim with their insurer, an adjuster is assigned, and the victim negotiates a settlement or, if necessary, litigates against the policy.
Insurers, however, commonly exclude certain breeds or impose conditions. Breeds frequently excluded from standard policies include pit bulls, rottweilers, German shepherds, chow chows, Doberman pinschers, Akitas, and wolf hybrids. If a dog falls into an excluded category, a bite claim may come out of the owner’s own pocket. Some insurers will still cover excluded breeds if the owner agrees to conditions such as fencing or muzzling, and specialty carriers offer breed-specific liability policies.
Owners should read the animal liability section of their policy closely. A dog already declared dangerous under Section 157 will typically trigger a premium increase or non-renewal, and because treble damages apply to any later bite by that dog, being uninsured at that point carries serious financial exposure.