Why does my puppy bite everything?
Quick answer
Biting is normal puppy behaviour, not aggression. Puppies explore with their mouths and chew to relieve teething pain. Redirect onto a chew toy every time, and never onto hands.
Almost every new puppy owner worries about biting in the first few weeks. In nearly all cases it is completely normal. Puppies have no hands, so they investigate the world with their mouths, and between roughly three and seven months old they are also teething, which is genuinely uncomfortable.
What matters is not stopping the behaviour but redirecting it.
Keep a chew toy within reach
When teeth land on skin, calmly swap in the toy. The message you want to send is not that biting is bad, but that this is the thing to bite.
End the game when teeth touch skin
Stand up, turn away, and stop playing for about twenty seconds. Puppies want your attention more than anything, and losing it briefly is the clearest feedback there is. Shouting or physical corrections tend to make puppies more excited, not less.
Do not use your hands as toys
Wrestling with bare hands teaches exactly the habit you are trying to prevent, and what is charming from a small puppy is painful from a grown dog.
Check whether it is overtiredness
Puppies need a surprising amount of sleep, often sixteen hours or more a day. A puppy who suddenly turns into a shark late in the evening is frequently just exhausted. Try settling them somewhere quiet before assuming it is a training problem.
Most puppies grow out of mouthing as the adult teeth settle in and impulse control develops. Consistency matters more than any single technique: everyone in the household needs to respond the same way, or the puppy simply learns who they are allowed to bite.
When to call a vet
Book a vet visit if biting is paired with growling, stiffness or guarding over food and objects, if your puppy yelps when you touch their mouth, or if they suddenly become mouthy after previously being gentle. A pain response can look like temper.