Double Trouble? Why Getting Two Puppies from the Same Litter Isn’t Twice the Fun

Bringing home a puppy is exciting—there’s just something about a wagging tail and tiny paws that melts your heart. And when you’re looking at a whole litter of fluffy little faces, choosing just one? Nearly impossible. So, you start thinking… maybe two wouldn’t be so bad. They’ll keep each other company, right? We get the appeal. But as professional dog trainers (and major dog lovers), we’ve seen how that decision can create more stress than smiles down the road. It can cause something known as littermate syndrome, and if you’ve never heard of it, you’re not alone—but it’s something every future dog owner should understand before getting two puppies from the same litter.

What is Littermate Syndrome?

Littermate syndrome is a common term used in the dog training world to describe a pattern of behavioral issues we often see when two puppies from the same litter are raised together in the same home. When puppies are never separated and rely too heavily on each other, it can interfere with proper emotional development. Pups who are bonded so closely to one another often can’t function well alone and struggle to bond with their humans and interact with the outside world in a healthy, confident way.

Red Flags with Two Puppies from the Same Litter

We typically start seeing signs of littermate syndrome around six to nine months of age. Some of the issues we run into most often include:

Separation Anxiety: These pups have rarely been apart, so when life does separate them (for vet visits, walks, grooming, etc.), one or both can completely fall apart. It’s not just whining—it’s panic-level stress.
Lack of Bonding with Humans: When the puppies are each other’s entire world, it’s harder for them to connect with you. You may notice they ignore your commands, seem uninterested in play, or are just flat-out disengaged.
Social Struggles: Since they mostly just hang out with each other, these pups often miss out on learning how to interact with other dogs and people. This can turn into fear, reactivity on leash, or even aggression.
Aggression Between Siblings: As the littermates grow up and start defining their roles in the “pack,” things can take a turn. While not as common as the other symptoms, we’ve seen siblings start to show serious aggression toward each other, sometimes out of the blue.

Why It’s So Hard to Train Two Puppies from the Same Litter

Training one puppy is a full-time job. Training two puppies from the same litter is a whole different challenge. If they’re always together, they tend to feed off each other’s energy and distractions. What you end up with are two dogs who behave chaotically the moment you ask them to do something separately.

And we get it: the intention behind bringing home two is usually love. But even the most devoted dog owner can get overwhelmed when both puppies start developing behavioral issues that seem to escalate in sync.

If You Already Have Two Puppies from the Same Litter, Here’s What You Can Do

If you’ve already brought home this kind of dynamic duo, don’t panic. There are ways to raise healthy, well-adjusted siblings—it just takes a lot of intentional work and structure. Here’s what we recommend:

Separate Everything (Seriously): That means individual walks, training sessions, crate time, playtime, and social outings. Your goal is to build up each puppy’s confidence away from their sibling so they can learn to rely on you instead.
Start Training Early and Often: Don’t wait for the problems to start—get help early. Working with a professional trainer, like our team here at BlackPaw, can save you months (or years) of stress. You’ll need to devote extra time and energy to each pup if you want them to thrive.
Be the Leader They Need: Dogs need structure, boundaries, and consistent leadership to feel safe and secure. Without it, they’ll often take matters into their own paws—usually in ways that don’t benefit anyone.

At BlackPaw, we’ve worked with plenty of families who found themselves in over their heads after bringing home two puppies from the same litter. And we’ve helped those same families create a calmer, more balanced home life through our Puppy Head Start program. It’s tailored to help each dog learn independence, build trust with their humans, and grow into confident companions.

Final Thoughts

We know the heart wants what it wants—and sometimes, the heart wants two puppies. But before you bring home the whole crew, it’s worth weighing the long-term challenges that can come with littermate syndrome.

With the right structure, support, and training (and yes, a lot of patience), it is possible to raise siblings who become wonderful family dogs. But for most families, one puppy is more than enough to love, train, and enjoy for years to come.

Got two pups already and not sure where to start? We’re here for you. Whether you need guidance, hands-on training, or just someone to talk through next steps—we’re just a message away.