Best Dog Collar for a Boston Terrier: Size, Fit, and Style Guide
June 25, 2026 · 5 min read
Boston Terriers are dapper little dogs, flat-faced and lively, with a head that can be narrower than you would expect. That shape means a regular collar can slip off, so fit needs a little extra care. Here is how to size a collar for your Boston.
Boston Terrier collar size at a glance
Bostons range from small to mid-sized. Measure your own dog and check the slip test below.
| Measurement | Range |
|---|---|
| Neck circumference | 12-18 in (30-46 cm) |
| Typical weight | 10-25 lbs |
| Recommended Dazey size | M, sizing up to L for larger Bostons |
How to measure your Boston Terrier's neck
The number on the size chart only works if you measure first. Wrap a soft tape measure or a piece of string around the base of your Boston Terrier's neck, where the collar naturally sits, then keep it snug but not tight. The gold standard is the two-finger rule: you should be able to slip two fingers between the collar and the neck once it is buckled. For the full walkthrough see our dog collar size chart, or let our sizing calculator do the math for you.
- Measure the base of the neck where the collar sits, not up near the head.
- Keep the tape snug, then add room for two fingers.
- Measure to the skin, not over thick fur, so the collar is not secretly too loose.
- If you land between two sizes, size up and use the adjustment range.
Fit notes for Boston Terriers
The Boston's slip risk comes from a head that can be narrow relative to the neck, so a collar at a normal fit can pull off over the ears if the dog backs up. Verify a true two-finger fit, then test it: gently see whether the collar can slide forward over the head. If it can, a martingale collar or a harness is the safer choice.
Bostons are also brachycephalic (flat-faced), so keep pressure off the airway with a gentle fit and a softer, wider webbing. For walks with any pulling, a harness protects that short throat while the collar carries ID.
Choosing a style your Boston Terrier can pull off
A Boston's tuxedo coat is a perfect backdrop for a bright pattern. A cheerful look like our Sunny Smiles collar plays up their fun personality. Browse the rest of the Dazey collars for more everyday styles.
Quick fit reminders for Boston Terriers
Do the slip test
After fitting, check that the collar cannot slide forward over the head. If it can, choose a martingale or harness.
Gentle on the airway
As a flat-faced breed, keep a soft two-finger fit and consider a harness for walks.
Wider is kinder
A slightly wider, soft webbing spreads pressure better than a thin strap.
Find the right collar for your Boston Terrier
Fit it, slip-test it, and pick a look as sharp as that tuxedo coat. Every Dazey collar is soft, durable, and adjustable. Shop Dazey collars and find the right size for your Boston Terrier.
Frequently asked questions
What size collar does a Boston Terrier need?
Most Boston Terriers measure about 12 to 18 inches at the neck, which is a medium, sizing up to a large for bigger dogs. Measure your dog and confirm it cannot slip over the head.
Why does my Boston Terrier slip out of its collar?
Bostons can have a head that is narrow relative to the neck, so a normally fitted collar can pull off when they back up. Tighten to a true two-finger fit, and if it still slips, use a martingale collar or a harness.
Should a Boston Terrier use a harness?
For walks, often yes. A harness avoids both the slip risk and pressure on a flat-faced dog's airway, while a lightweight collar is ideal for everyday ID.
Siobhan Hanak
Head of content
Siobhan leads content at Dazey, telling stories and writing guides for dogs and the people who love them.