What to Expect With A New Puppy: The First 6 Months

It’s no secret that puppies grow quickly. But once you bring your new puppy home, you’ll soon realize that every stage of puppy development is just as important as the next.

When your puppy joins your family—sometime between the age of 8 and 14 weeks—you’ll discover that every month comes with something new.

One Month (0-4 Weeks)

Also known as the neonatal and transitional stages, this part of your puppy’s life will progress quickly. By weeks 2 and 3, your puppy’s eyes and ears begin to open. Then they begin to get their bearings and take their first puppy steps.

By week 3, your puppy has stumbled upon one of the most important puppy milestones: the The socialization period spans about 3 to 16 weeks. At this time in a puppy’s development, they’re most open to learning.

Puppies during the socialization period may experience 

Key puppy milestones at one month:

• Newborn: Puppies can sense body heat, smell, suckle, and crawl.
• Week 2: Puppies begin developing baby teeth.
• Week 2-3: Puppies’ eyes and ears open.
• Week 4: Puppies can stand and take their first steps.
• Socialization period: Puppies express fear when separated from their mother and littermates.

At this stage, puppies are still too young to leave their mothers. They need her milk for nutrients, but they also need to learn important social skills from her and their littermates, explains National Dog Training Manager at Petco.

Two Months (4-8 Weeks)

By 4 or 5 weeks, puppies are starting to go, go, go. They’re wobbling around beyond the comfort of mom and seeking out play with littermates and human caregivers. It’s a busy month for puppies for other reasons too: They’ll begin weaning and using the bathroom on their own.

By month 2, you can start Puppies are still too small to “hold it” for long, so they’ll need hourly potty breaks with consistent positive reinforcement.

Key puppy milestones at two months:

• Week 4-5: Puppies seek out play with littermates and human caregivers.
• Week 5: Potty training begins.
• Week 6-8: Puppies receive their first set of core vaccines.
• Week 7: Puppies can fully transition to solid food.
• Week 8: Puppies may be ready to join their forever family.
• Week 8-10: Your puppy has a full set (28 teeth) of baby teeth.

Toward the end of month 2, your puppy’s caregiver will consult a veterinarian about 

Core vaccinations, which occur between 6 and 8 weeks, include distemper, adenovirus, parvovirus, and parainfluenza (collectively called DAPP). After your puppy comes to you, they’ll need two more boosters of the DAPP vaccine. Depending on where your puppy lives and their expected lifestyle, they may receive other, optional vaccines.

Cooper says most puppies are old enough to leave their mothers and littermates by 8 weeks, but the ideal age will vary depending on the breed of dog and the puppy’s individual socialization. Some puppies leave their mom as late as 14 weeks old.

Three Months (8-12 Weeks)

Your puppy is the most impressionable during this period, Cooper says. And while it’s important to continue introducing them to new stimuli as they near the end of the socialization window, keep in mind that 

Key puppy milestones at three months:

• Puppies can leave their mom and go to their forever home.
• Puppies weighing at least 2 pounds may be old enough for spaying or neutering.*
• Puppies get their second set of core vaccines.
• Fear of new things develops, and puppies rely on their pet parents for comfort.
• According to Cooper, puppies form their deepest relationships with their pet parents at three months.

“It’s important for pet parents to be patient during this time and create as many good experiences for their pups as possible using positive reinforcement,” Cooper says. This may include  so that they don’t develop a fear of being left alone with a stranger. “If your puppy does get scared, be sure to offer comfort.”

He suggests pairing new “scary” experiences with something positive, like puppy treats or play. This is called and if you sign your puppy up for obedience classes (Cooper recommends it!), your puppy is sure to get lots of practice.

*Most shelters and rescues will send puppies home spayed or neutered to prevent intentional breeding. However most vets recommend waiting closer to the 6-month mark or longer before you

Key puppy milestones at four months:

• Puppies start to lose their baby teeth and develop their permanent, adult teeth.
• Puppies get their third set of core vaccines, plus their 
• Your puppy will have plenty of energy, but theym as long as adult dogs.
• Reliance on consistent and clear communication from pet parents accelerates at this age.

Teething aside, your puppy’s unique personality will start to emerge around the age of 12 weeks. They’ll need continued socialization to develop good social skills, practice potty training, and become an overall well-mannered pup. Controlled play with other dogs is a great way to achieve this.

Five Months (16-20 Weeks)

Your curious puppy will start to show their independence. Just keep in mind that their exploration—or pushing the boundaries on house rules—isn’t “naughty,” but part of their development.

To prevent your puppy from getting into trouble, if you haven’t already. This may involve:

• Using baby gates to restrict access to certain rooms
• Buying puppy-proof cabinet latches and garbage cans

Key puppy milestones at six months:

• Most puppies have nearly finished growing, except for large and giant breeds.
• Teething stops, as your puppy has all of their adult teeth.
• Your 6-month-old puppy can now hold their pee for about 6 hours, Cooper says.

Getting Ahead of Dog Adolescence

“Much later during puberty, dogs undergo significant hormonal changes, like human teenagers,” Barton explains. “This can change and intensify dogs’ emotions, so caregivers should be especially patient with their dogs during this period.”

These stages can be tough on the allow your dog to follow their nose and explore at their own pace.

Your dog’s “teenage” behavior may feel frustrating at times, but it’s important to stick with reward-based training and socialization. This will help your dog learn how to behave appropriately in different situations and as they reach emotional and sexual maturity.