How long before a puppy can leave it's mother?!
A puppy leaves its mother after eight weeks. There are many breeders who wait until the puppy is ten to twelve weeks old for the reason that, the last few weeks of mother's milk helps the immune system.
Mist people will take puppies away from their mother at 8 weeks. That's actually a bit early. Optimally it shouldn't be until about 12 weeks.