Yes, dogs can have mozzarella cheese in moderation. Mozzarella is not toxic to dogs and is lower in fat and lactose compared to many other cheeses, making it a safer option as an occasional treat. It also contains beneficial nutrients like vitamins A and B, calcium, and protein. However, some dogs may be lactose intolerant, so mozzarella could cause upset stomach or digestive issues in those cases. Additionally, feeding too much cheese can lead to weight gain and related health problems like obesity. It is best to consult a veterinarian before introducing mozzarella or any human food into a dog's diet and keep the portions small and occasional.