In this article
At sixteen weeks your puppy sat the moment you asked. At eight months, the same dog stares straight through you at the park, then sits beautifully for the dog walker. If you have started to wonder what you did wrong, you are in good company, and you are probably not imagining it.
Trainers have talked about a teenage phase in dogs for years, and in 2020 a UK team published what they believe is the first scientific evidence for it1. Here is what they found, how long the phase lasts, why getting tougher backfires, and a plan for the months in between.
What the guide dog study found
The UK team, led by Lucy Asher at Newcastle University, studied guide dog puppies in the care of Guide Dogs UK puppy walkers, the carers each pup lives with from about two or three months old until it is 12 to 14 months1. They tested 93 Labrador and golden retrievers and crosses on one simple, well-practised cue: sit1.
At eight months, the odds of a puppy repeatedly ignoring "sit" from its carer were about twice as high as at five months1. Yet when a stranger asked, the puppies did better than they had at five months, with the same carer and stranger both times1.
Questionnaires on 285 dogs told the same story: carers rated their dogs less trainable at eight months than at five or twelve, while trainers who knew the dogs less well rated them more trainable at eight months than at five1.
The dip in obedience to the carer was more marked in dogs whose behaviour suggested a less secure attachment1. There are limits. These were guide dog puppies of a few breeds on a standard programme, and puberty was not measured in every dog, only assumed from typical ages for those breeds1. Their conclusion is still a hopeful one.
In most dogs, it seems that adolescent-phase disobedient behaviour exists, but does not last1.
When it starts and how long it lasts
There is no fixed date. PDSA's vets put the start of adolescence at around 8 to 12 months, varying with breed and size, since bigger breeds tend to mature more slowly. They add that most dogs are not fully socially mature until they are about three4.
Pet dogs have their own long-term study, Generation Pup, which follows puppies in the UK and Ireland as they grow up. In a 2025 analysis, researchers at Dogs Trust explain that for most dogs puberty arrives somewhere between six months and a year, depending partly on breed, and that some adolescent development carries on between one and two years old2.
The same analysis looked at what owners wrote, in surveys at five ages, about any behaviour they found a problem. The share of dogs with at least one peaked at 12 months, when it was reported for 513 of 1,219, then fell2.
Dogs with at least one behaviour their owner found a problem
Barking was the most common complaint at every age, and barking, pulling on the lead and recall problems all peaked at 12 months before declining2. Yet at every age, more than half of the dogs had no problem behaviour reported at all2.
Why the numbers fall is less clear. The researchers cannot tell whether dogs matured, owners trained them or owners got used to it, and the families were volunteers who may not mirror every home2.
What is going on in a teenage dog's head
Some of it is hormones. As dogs reach sexual and social maturity, PDSA explains, males often start humping, urine marking and roaming more, and females can become anxious or nervous during their seasons4. Some dogs turn more territorial, barking at things that never used to bother them, and some come to enjoy other dogs' company less4.
Attention seems to be changing too. Researchers in Vienna tested 145 Border collies, aged from six months to 14 years, on a task where, after eating a treat tossed on the floor, a dog had to look up at a person's face to earn the next one3. The adolescents, aged one to two, were slower to make that switch than middle-aged dogs, and the team's likeliest explanation was weaker attention control or greater distractibility3.
Then came the encouraging part: over 20 practice turns, the adolescents' times improved more steeply than the middle-aged dogs' did, though they had started further behind3. It was one breed, with different dogs at each age, but the message is cheering: a teenage dog may be easily distracted, yet can improve quickly with practice. That is a good reason to keep sessions short and winnable.
Confidence can wobble as well. The Royal Kennel Club notes that between about 6 and 14 months, some young dogs become fearful of things and people they used to greet happily5. Its advice is to go back to the steps you took to socialise your puppy, building plenty of positive experiences with treats, play and fun5.
Why getting tougher backfires
When a dog who knew "sit" stops sitting, it is tempting to get firmer. PDSA's vets advise against punishing a dog for this, warning that punishment harms a dog's mental wellbeing and risks making problems worse4. The stakes are higher than a missed sit: both research teams note that adolescence coincides with a peak age for dogs being given up1, 2.
Harsher methods have been studied directly. Researchers in Portugal compared 92 pet dogs from seven training schools, some using rewards and some using aversive methods such as lead jerks, yelling and slapping7. Dogs at the most aversive schools showed more stress behaviours in class, such as lip licking and yawning, and bigger rises in the stress hormone cortisol after training than dogs at the reward-based schools7.
In a separate test away from class, those dogs were also slower to approach a food bowl than the reward-school dogs, which the researchers read as a sign of a less positive mood7. The dogs were not assigned to schools at random, so the study cannot prove cause and effect7. It does match the welfare charities' advice, and it is hard to see what a distractible teenager gains from being frightened.
Pulling back is the quieter trap. The guide dog researchers warn that welfare could suffer if teenage behaviour pushes owners towards punishment, or leads them to disengage1. What builds a more secure bond is still a question for future study, they say1, but keeping up the good parts of your days together costs nothing: the games, the walks you both love, the quiet evenings on the sofa.
A reset plan for the teenage months
Think of the next few weeks as making it easy for your dog to get things right. Dogs Trust's everyday training tips suit a distractible teenager well.
Back to basics, step by step
- Make it easy againPractise known cues at home, somewhere calm and free of distractions, before trying them outside8
- Pay wellReward with praise or a tasty treat, and mix up what you use to keep it interesting8
- Keep it shortFive to ten minutes on one skill, then end the session with a fun game8
- Go back a stepIf your dog is struggling, stop, and progress more slowly next time8
- Write it downFilm your sessions or note progress, so you can see it on the slow weeks8
Then manage what training has not fixed yet. If recall has slipped, the Royal Kennel Club suggests swapping full off-lead freedom for a long line your dog can trail behind them, and it advises against retractable leads, which give too little control5.
The club's view is that with the line and plenty of rewards when your dog comes back, the slip in recall should not last long, but a young dog who learns they can ignore you may keep it up far longer, or make a habit of it5. Every missed recall you prevent is one less chance to practise ignoring you, so for now, ask for things when your dog is likely to manage them.
When to call in help
For most dogs, the research suggests, the teenage wobble passes1. Still, PDSA points out that many behaviour problems get worse over time, and that if you cannot tell a real problem from ordinary adolescence, it is safest to get your dog checked4.
After that, look for qualified, reward-based help, and your vet can refer you to a behaviourist. Dogs Trust points to the Animal Behaviour and Training Council's database of accredited trainers. For the more emotional problems, such as fear and anxiety, it suggests a behaviourist, and names CCAB, the independent body that accredits Certificated Clinical Animal Behaviourists, as a good place to find one. Anyone can call themselves a behaviourist, it warns, so check qualifications first6.
Neutering often comes up at this age. PDSA says it may help with some teenage behaviour changes, and will stop a female's problems that come from her seasons. It is not the answer to every problem, it adds, and training must carry on either way4. Whether and when to neuter is a conversation to have with your vet.
The puppy who sat so nicely at sixteen weeks is still in there, growing up. Keep the lessons short, the rewards generous and the long line handy, and give your dog the time to come through it.
Sources and further reading8 sources
The small numbers in the article link to the source behind each fact. Sources open on their own websites.
- Teenage dogs? Evidence for adolescent-phase conflict behaviour and an association between attachment to humans and pubertal timing…
- Owner-Perceived Undesirable Behaviours in Young Dogs and Changes with Age
- Lifespan development of attentiveness in domestic dogs: drawing parallels with humans
- Adolescent (Teenage) dogs
- Your growing puppy: adult and teenage years
- Finding behaviour and training support
- Does training method matter? Evidence for the negative impact of aversive-based methods on companion dog welfare
- Top 10 dog training tips