Maybe. Pups do not process fat as easily as we humans do, so milk should only be served on occasion. Dogs may also be lactose-intolerant; you will recognize if your dog has loose stool or bad gas after eating dairy, usually.
If your dog isn’t lactose-intolerant, then lessen-fat milk lack of added sugar should result few problems. Don’t permit your dog to drink chocolate milk, of course, since chocolate can be fatally dangerous for dogs.
If your pup has any uncommon symptoms after drinking milk, talk to your veterinarian about whether your dog could have a lactose intolerance or dairy allergy.
You should note that symptoms of lactose intolerance will show up as digestive problems, while a true dairy allergy leads to symptoms like watery eyes, itchy skin, and pitiful coat quality.