The Dog Teenage Phase: When It Starts, What to Expect and How to Get Through It

When Does the Dog Teenage Phase Start and End?

There's no single birthday. Most puppies hit adolescence around 6 months, and it generally ends around 18 months but can run to 2 years (Cornell). One proposed research system classes 1- to 2-year-olds as young adults still finishing adolescent development (Harvey, 2021).

Size and breed both affect puberty (Merck). First heats range from 4 months in some small breeds to 24 months in some large breeds (AAHA 2019), so a small dog may be in full teenage swing while a giant-breed puppy the same age is still growing.

What the Research Shows: Teenage Dogs Really Do Tune You Out

The best evidence comes from a 2020 Biology Letters study of prospective guide dogs living with volunteer carers in the UK (Asher et al.):

• The "sit" test. 93 Labradors, Golden Retrievers and crosses were tested at 5 months, 8 months or both. At 8 months, the odds of repeatedly ignoring "sit" from their carer roughly doubled (odds ratio 2.14), while responses to a stranger improved.
• Carer ratings. Across 285 dogs, carers rated trainability lower at 8 months than at 5, and higher again by 12 months. Trainers who knew the dogs less well rated them more trainable at 8 months.
• Attachment. Separation-related behavior scores were 36% higher at 8 months, and dogs with higher scores were less obedient to their carer at 8 months. Females that were clingier at 5 months reached puberty earlier.

So the dip targets the person the dog knows best, and it passes. It isn't a bid for "dominance," a framing AVSAB advises against. Whether pet dogs show the same pattern hasn't been tested; these were guide-dog puppies of three breed types. The authors warned that the phase overlaps with the peak age for shelter surrender, and that punishment or disengaged owners could harm welfare.

Signs Your Dog Is in the Teenage Phase

• Selective hearing. Ignoring the recall and "forgetting" known cues (Cornell). Our recall guide shows how to rebuild it.
• Rule testing. Darting out the door, tantrums when denied a treat, barking for no obvious reason (Cornell).
• More chewing. Adult teeth are usually in by about 6 months (VCA), but AKC describes a second chewing phase at 8–10 months.
• Bigger and bolder. Teens are stronger and keen to explore beyond their old comfort zone (AKC), so jumping up and leash pulling get harder to ignore.
• Sexual maturity. A first heat in females; in males, watch for urine marking, mounting and roaming, the behaviors castration most reduces (Neilson et al., 1997).
• New wariness of things that never bothered your dog before (AKC).

Is There a Second Fear Period?

Trainers commonly describe one. AKC places it generally between 6 and 14 months and says fear periods appear suddenly and usually last no more than two weeks. But AKC cites no studies, and research on how puberty affects dog behavior is limited (Harvey, 2021), so treat it as a rule of thumb.

Scary experiences do leave a mark. Among 978 prospective guide dogs, puppies frightened by a person while being raised were far more fearful of strangers at 12 months (odds ratio 4.60), and those threatened by an unfamiliar dog were more fearful of dogs (Serpell & Duffy, 2016).

If your teen suddenly startles at the recycling bin, don't lure them closer with treats, which AKC says can backfire. Reward calm or curious looks from a distance your dog chooses. If fear lasts or spreads, see your vet and a trainer experienced with fear (AKC).

Why It Happens

• Hormones and growth. Hormones for growth and sexual maturity switch on (Cornell), though AAHA says the behavior changes of social maturity aren't linked to hormones.
• A still-developing brain. Cornell says the prefrontal cortex, which handles self-control, is still maturing, as in human teenagers. Mammal brains do reorganize in adolescence, but dog-specific evidence is limited (Harvey, 2021).
• The relationship. Because the dip targeted only the carer, Asher's team argued it reflects more than hormones and brain changes.

A Practical Plan for the Teenage Months

Lower the bar, then rebuild

Go back to the last step your dog got right and add difficulty in small steps (AKC; Cornell). If you keep repeating a cue, AKC says your dog probably doesn't understand it there; say it once, make it easier, and reward. In exciting places, ask for an easy sit or nose touch to regain attention. Even five minutes of training a day helps (Cornell).

Pay more, more often

Rewards beat aversives: in a survey AVSAB cites, obedience was highest with reward-only training and lowest with aversive-only training (Hiby et al., 2004). Use what your dog loves, food or play, and reward good choices made unasked, like sitting for attention (AKC). Cornell also suggests asking for a sit before anything your dog wants.

Manage the house so mistakes don't get practiced

• Put tempting items away, use baby gates and offer plenty of acceptable chew toys (Cornell).
• Crate your dog when you can't supervise, even if they're house-trained (Cornell); see our crate training guide.
• For a door-darter, add a gate and leash until your dog can sit and wait for a release cue (Cornell).
• For jumping and barking, AVSAB recommends arranging the environment and rewarding the behavior you want; for a jumper, that can mean treats for four paws on the floor. Our puppy behavior fixes cover more.

Exercise the body and the brain

Cornell suggests long walks, swimming and free running in a safe yard, plus brain work: reviewing basics, shaping or clicker games, and scent games. Try these indoor activities for high-energy dogs, or our Border Collie and Labrador puppy checklists.

Keep socializing, gently

Let your dog watch from a comfortable distance and leave when they want; AAHA warns that forcing fearful dogs to stay makes fear worse.

Skip punishment

AVSAB advises against choke, prong and shock collars, leash jerks, shouting, squirt bottles and "alpha rolls," and says dogs should always be able to opt out of training. At one behavior clinic, confrontational methods provoked aggression in many dogs: 43% when hit or kicked, 31% after an alpha roll (Herron et al., 2009). Dogs at schools using many aversive methods showed more stress behaviors and bigger cortisol rises than reward-trained dogs (Vieira de Castro et al., 2020).

Heat Cycles, Hormones and the Spay/Neuter Question

An intact female's first heat typically comes at 10–12 months (Merck). Heats recur about twice a year, and she attracts males through proestrus and estrus, each about 9 days on average (Merck), so keep her leashed and supervised outdoors.

Timing advice is now individual. AAHA suggests about 5–6 months for dogs expected to weigh under 45 lb as adults; for larger dogs, males once growth stops (usually 9–15 months) and females case by case. UK guidance from the BVA and BSAVA (2026) puts most dogs at 12–24 months, and AVMA says there's no one-size-fits-all age. See our guide to when to spay or neuter a dog.

Don't count on surgery to fix teen behavior. Castration after age 2 cut marking, mounting and roaming by at least half in 60% or more of dogs, but aggression improved that much in fewer than 35% (Neilson et al., 1997). A survey of more than 13,000 dogs found no link between neutering and aggression toward familiar people or dogs, though dogs neutered at 7–12 months were 26% more likely to be aggressive toward strangers (Farhoody et al., 2018).

When to Get Help

• See your vet first for fear or withdrawal, aggression, new phobias, distress when alone, increased reactivity, house-soiling or big activity changes, which AAHA says warrant veterinary assessment. A review conservatively estimated that about a third of behavior cases referred to specialists involve pain (Mills et al., 2020).
• A certified, reward-based trainer for jumping, pulling and manners (AAHA). Look for CCPDT or IAABC credentials and ask which tools they use; AAHA says to switch trainers who jerk leashes or talk about "dominance." For lunging on walks, see our leash reactivity guide.
• A veterinary behaviorist for aggression, bites, panic or worsening fear; AAHA says aggression should never go to a trainer for primary treatment. Find a board-certified specialist through the American College of Veterinary Behaviorists directory; they can prescribe medication, which AVSAB says may be needed for serious fear or aggression.

It Does End: Why Sticking With It Matters

Adolescence is when many dogs lose their homes. In a 1995–96 study of 12 US shelters, 47.4% of surrendered dogs were 5 months to 3 years old, and 46% had been owned less than a year (Salman et al., 1998).

The good news: carers' trainability ratings in Asher's study rebounded by 12 months, and AAHA says many dogs emerge from social maturity calmer and more attentive. But AAHA also says there is no evidence that pets "grow out" of behavioral problems. Wait out the selective hearing, not fear or aggression. If you're considering rehoming, talk to your vet or a certified trainer first.

Written by Kailun Zhang, who is not a veterinarian or certified trainer. It summarizes the sources below and isn't a substitute for advice from your vet or a qualified behavior professional.

Frequently Asked Questions

At what age do dogs go through the teenage phase?

Most puppies enter adolescence around 6 months, and it generally winds down around 18 months, sometimes lasting to 2 years (Cornell). Puberty comes later in large and giant breeds: a first heat can arrive anywhere from 6 to 24 months (Merck).

How long does the dog teenage phase last?

Typically from about 6 months to 18–24 months, depending on breed and individual (Cornell). Full social maturity comes at 12–36 months (AAHA 2015).

Why does my 8-month-old dog suddenly ignore me?

It's probably adolescence. Guide-dog puppies at 8 months had about twice the odds they'd had at 5 months of repeatedly ignoring "sit" from their main carer, but not from a stranger, and carers' trainability ratings rebounded by 12 months (Asher et al., 2020). Make things easier and reward generously; see your vet if the change is sudden or comes with fear or pain.

Do dogs have a second fear period?

Trainers commonly describe one between about 6 and 14 months, usually lasting no more than two weeks (AKC), but AKC cites no studies for it. Don't push your dog toward what scares them; reward calm from a comfortable distance, and see your vet if the fear lasts or spreads.

Will spaying or neutering calm my adolescent dog down?

Probably not much. Castration mainly reduces urine marking, mounting and roaming (Neilson et al., 1997), and AAHA says the behavior changes of social maturity aren't linked to hormones. Decide on timing with your vet based on size, breed and health.

Should I be stricter with a teenage dog?

Be more consistent, not harsher. AVSAB advises against leash jerks, shouting and alpha rolls, and in one clinic study confrontational methods provoked aggression in up to 43% of dogs (Herron et al., 2009). Manage the environment and reward what you want.

Related Reading

• How to Teach a Dog Recall: A Step-by-Step Plan for Coming When Called
• Leash Reactive Dog: Why Your Dog Lunges at Other Dogs and How to Help
• When to Spay or Neuter a Dog: The Best Age by Size, Breed and Sex
• Complete Guide to Crate Training Your Dog
• Puppy Behavior Solutions: 5 Common Issues
• 5 Indoor Activities for High-Energy Dogs
• Easiest Dogs to Train
• Border Collie Puppy Checklist
• Labrador Retriever Puppy Checklist
• Dog Training Guides
• Dog Health Guides