Mastiff Adoption in Ontario: Mastiff Puppies for Sale in Ontario

Adopt a Mastiff near you in Ontario

Below are our newest added Mastiffs available for adoption in Ontario. To see more adoptable Mastiffs in Ontario, use the search tool below to enter specific criteria!

Diesel

Mastiff

Male, 2 yrs

Hamilton, ON

Size

(when grown) Large 61-100 lbs (28-45 kg)

Details

Good with dogs, House-trained,

Story

Built like a tank but powered by a very relaxed engine, Diesel is a 2-year-old Mastiff cross who is looking for a home where he can cruise comfortably through life. Diesel arrived as an unclaimed stray alongside another dog believed to be his littermate, and it’s clear he takes comfort in canine company. With a dog friend by his side, his confidence really shines. When he’s on his own, Diesel may take a moment to read the room and assess his surroundings but once he realizes everything is safe, he settles in nicely and continues on his way. Despite his size, Diesel is actually a lower-energy kind of guy. He’ll have a quick burst of goofy, puppy-like zoomies now and then, but they’re short-lived before he returns to his favorite activities: lounging, observing the world, and enjoying a peaceful nap. In his kennel he keeps things tidy and calm, and when passing by other dogs he’s friendly and polite. Diesel is also a smart cookie. He already knows “sit” and “paw,” and he’s very motivated when treats are involved. Because of this, he would really benefit from positive reinforcement obedience classes to help him learn more tricks and establish clear boundaries and routines in his new home. When meeting people, Diesel is polite and respectful - not the jumpy, over-the-top greeter type. He prefers a calm introduction and appreciates someone who can read his body language and give him a moment when he needs it. Because of this, we recommend a home with somewhat experienced handlers and no young children, where his cues will be understood and respected. In a perfect world, Diesel’s new home would include: possibly another friendly dog companion, daily walks and mental enrichment, a cozy sunny spot for naps and a yard where he can stretch out in the grass. During his medical exam Diesel allowed staff to check his ears but was a little tense during his dental check - understandable for a new environment. He'll need a more experienced home familiar with cues that he's uncomfortable. He has mild tartar on his molars, but no dental procedure is needed at this time. A dental-support diet is recommended to help keep that handsome smile healthy. Diesel is a gentle, thoughtful boy who just needs a patient home to help him continue building confidence and enjoying the good life he deserves. If you’re looking for a loyal companion with a calm nature, good manners, and the occasional burst of goofy energy, Diesel might be the perfect co-pilot for your next chapter. Please complete an adoption application: https://www.hamilton.ca/home-neighbourhood/animals-pets/adopt-or-foster-pet/adoptions Diesel has a future appointment to be neutered and will be ready to go to his forever home after his surgery. Animal adoptions and viewing are by appointment only. This allows our Adoption Staff to spend quality time with each potential home to ensure the most successful matches are made between the animals and their new families. *Please note: we only adopt within Ontario

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Charlie

Mastiff

Male, 6 yrs 1 mo

Kingston, ON

Size

(when grown) Large 61-100 lbs (28-45 kg)

Details

Story

Meet Charlie!Joined us in: January 2026About Charlie:· A sweet, people-loving boy who thrives on companionship.· Absolutely obsessed with stuffed toys — he loves carrying one around like his emotional support stuffy. ??· Knows “sit” and “paw” — such a polite gentleman!· Would enjoy having a yard where he can roam, explore, and stretch his legs.· Has a history of Lyme disease but is currently symptom-free.· On medication for skin allergies to keep him feeling his best.His perfect match:· A home with a yard and plenty of toys to keep him happy and engaged.· A family who enjoys a friendly, affectionate companion.· May do well with another low-energy, respectful dog pending introductions.· A great choice for a first-time owner.· Suitable for older, dog-savvy children who understand gentle interactions.Some extra facts about Charlie:· Forms lovely bonds with his people and enjoys being part of the family’s daily life.· His love for stuffed toys is unmatched — expect him to proudly parade them around the house.· With continued routine veterinary care for his Lyme history and skin management, he’s feeling great and ready for his next chapter.In short:Charlie is a gentle, toy-loving sweetheart who just wants a yard to explore, a stuffy to carry, and a family to adore. With love and ongoing care, he’ll be a devoted and delightful companion.

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Stella

Mastiff

Female, 2 yrs

Hamilton, ON

Size

(when grown) Large 61-100 lbs (28-45 kg)

Details

House-trained,

Story

At 2 years old, Stella is a beautiful Mastiff cross with a soft heart wrapped in a big, strong body. She arrived at the shelter as a stray alongside her presumed male littermate, and while the world can feel a little overwhelming at first, this sweet girl is showing us more of her gentle personality every day. Stella was understandably nervous during her medical intake, but she bravely allowed handling — and even showed off that she knows sit, down, and shake a paw! She takes treats ever so gently and is happily food-motivated, which makes her a wonderful candidate for continued training. With guidance and positive reinforcement, she’ll blossom into the very best version of herself. Though she can be timid when first meeting new people, Stella simply asks for a considerate, calm approach and a little patience. Once she feels safe, she absolutely melts — leaning her big frame into her person for cuddles, comfort, and reassurance. She bonds deeply and looks to her handler for guidance, making her a loyal and devoted companion. Stella appears to be housetrained and keeps her kennel tidy. She has been quiet during her stay and is described by staff as “shy but sweet” — a gentle giant finding her footing. While she can be selective with other dogs, she does warm up nicely and can enjoy playful interactions with well-matched canine friends. Because of her size and initial timidness — and her unknown history — a home without small children is recommended at this time. She will thrive with an experienced, patient handler who understands that trust is earned through kindness and consistency. As a large-breed girl, Stella will need daily exercise and plenty of mental stimulation to stay happy and healthy. Walks, enrichment toys, training sessions, and time spent bonding with her people will help her confidence grow beautifully. If you’re someone who appreciates the quiet, sensitive souls — the dogs who form deep, meaningful bonds — Stella may be your perfect match. Give her time, give her space, and she will give you her whole heart. Please complete an adoption application: https://www.hamilton.ca/home-neighbourhood/animals-pets/adopt-or-foster-pet/adoptions Stella has an appointment to be spayed on March 12th. She will be ready to go to her forever home after this surgery. Animal adoptions and viewing are by appointment only. This allows our Adoption Staff to spend quality time with each potential home to ensure the most successful matches are made between the animals and their new families. *Please note: we only adopt within Ontario

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London

Mastiff/Boxer

Female, 3 yrs

Guelph, ON

Size

(when grown) Med. 26-60 lbs (12-27 kg)

Details

Story

Hello! My name is London!I`m a fun and loving girl! I am snuggly and affectionate. I love treats and toys, which makes training a blast! I sometimes get excited and like to grab sleeves with my mouth. I thought that was fun but apparently humans don`t enjoy it as much as I do. No worries though, I`m super smart and doing well with training - I`m learning about other fun things to do instead. If you love cuddling, playing and snoring, I am definitely the girl for you!MY IDEAL HOME INVOLVES…CHILDREN: Teenagers should be fine. No young kids given I am still learning manners.OTHER DOGS: Potentially, it would have to be a very particular dog as I don`t like to roughhouse and I don`t like sharing my toys with dogs. If there is a dog in the home, he should be easy going, not exuberant, and not a resource guarder.CATS: Potentially, with cat experienced and confident around dogs.FIRST-TIME DOG OWNERS: I would do best with someone who has dog experience.FENCED-IN YARD: I do love to romp around outside while tossing toys in the air. A fence would be helpful to set me up for success.HOUSING ENVIRONMENT: Any, with yard preferred to help with exercise.SOMEONE HOME MOST OF THE DAY: Not necessarily.SOME OTHER THINGS TO KNOW ABOUT ME…ACTIVITY LEVEL: Medium.HOUSE-TRAINED: Yes.If you think I could be a good match for your home, click the “Adopt Me” button to apply!

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Violet

Mastiff

Female, Young

Stouffville, ON

Size

(when grown) -

Details

Story

Meet Violet! Violet is an absolute sweetheart, although she will likely be nervous of new people at first. She will take some time to warm up and trust, but after a short period of time in the shelter she has opened right up to staff and has become incredibly cuddly and playful! She has proven that she prefers women over men, but with a slow and considerate introduction, we feel that she will become comfortable with everyone. She is very head shy, so she does not like it when people try to grab her collar, or reach over her head to pet her. She prefers calm, slow movements which allow her to get used to your presence before touching. If you think your home is perfect for Violet, come by the centre any day from 11am-5:30pm to meet her and bring her home! Her adoption fee is $585 which includes her spay, vaccines, deworming, microchip, and a month's worth of FREE food! Primary Color: Brindle Secondary Color: Brindle Weight: 32.1 Age: 1yrs 0mths 3wks

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Rivendell

Mastiff/St. Bernard

Female, Puppy

Port McNicoll, ON

Size

(when grown) -

Details

Story

Spring is just around the corner! You know what goes great with outdoor activities? A PUPPY. Come take a peek at this cutie of a girl! She is sweet, and kind, and loves to nap just as much as she loves to play! Primary Color: Black Secondary Color: White Weight: 8.007 Age: 0yrs 0mths 11wks

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Below are our newest added Mastiffs available for adoption in Ontario. To see more adoptable Mastiffs in Ontario, use the search tool below to enter specific criteria!

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Mastiff puppies and dogs in Ontario

Jump to:

Adopt a Mastiff near you in Ontario

Below are our newest added Mastiffs available for adoption in Ontario. To see more adoptable Mastiffs in Ontario, use the search tool below to enter specific criteria!

Search for a Mastiff puppy or dog

Mastiff puppies and dogs in Ontario cities

Mastiff shelters & rescues in Ontario

Looking for a specific shelter or rescue?

Want to learn more about adopting a Mastiff puppy or dog ?

Mastiff information

Mastiff basics