Personal Injury · Dog Bite Liability
Dog Bite Laws in Massachusetts
Whether Massachusetts holds a dog owner automatically liable, follows the one-bite rule, or takes a mixed approach — plus landlord liability and the main defenses.
How liability works in Massachusetts
What the rule is, and what you must show.
Landlords & defenses
Who else can be liable, and what defeats a claim.
These are the only statutory exceptions — and for a child under 7, the defendant carries the burden to prove them.
The full picture, with the source
Every field, and any recent development.
| Liability model | Strict liability |
| Basis | Statute — Statute — M.G.L. c.140 §155 |
| What it covers | Any bodily or property injury counts (knocking someone over, chasing, or biting). A child under 7 gets a rebuttable presumption that they did not trespass or provoke — shifting the burden to the defendant. |
| Landlord | Generally no — liability runs to the "owner or keeper," and a landlord is not automatically a keeper. A landlord can be liable if they actually keep or harbor the dog, or through common-law negligence with knowledge and control. |
| Main defenses | Victim was trespassing or committing another tort · Teasing, tormenting, or abusing the dog |
What Massachusetts dog-bite victims get wrong
Massachusetts is one of the broadest strict-liability states: under M.G.L. c.140 §155 the owner or keeper is liable for any bodily or property damage a dog causes — not only bites, but also knocking someone down, chasing, or damaging property — without any proof of negligence or prior viciousness. The statute leaves only two exceptions: the victim was trespassing or committing another tort, or was teasing, tormenting, or abusing the dog. Massachusetts also protects young children: a child under seven is presumed not to have trespassed or provoked the dog, which flips the burden onto the defendant to prove otherwise. Landlords are generally outside the statute unless they truly keep or harbor the animal.
Common questions
Is Massachusetts a strict-liability dog-bite state?
Yes, and broadly so. Under M.G.L. c.140 §155 the owner or keeper is strictly liable for any bodily or property damage a dog causes — not just bites — subject to two narrow exceptions.
Does Massachusetts cover injuries other than bites?
Yes. The statute reaches any bodily or property damage, so being knocked down, chased, or having property damaged can all qualify.
What special rule applies to young children in Massachusetts?
A child under 7 is presumed not to have been trespassing or provoking the dog, so the defendant carries the burden to prove one of those exceptions.
What are the only defenses under the Massachusetts dog-bite statute?
The victim was trespassing or committing another tort, or was teasing, tormenting, or abusing the dog. There are no other statutory exceptions.
Not legal advicePlainStatute provides plain-language summaries of public law for general information only. This is not legal advice. Statutes change; always confirm current requirements with the official source linked above before acting.