Here are seven of the greatest guard dog breeds, renowned for their protective instincts, loyalty, and strength.

German Shepherds make great security dogs. They are popular for police, military, and home security because of their alertness, confidence, and trainability.

Rottweilers are fierce protectors and faithful family guardians. They can prevent threats with their intimidating presence with adequate training and socialisation.

Dobermans are known for their alertness, intelligence, and fearlessness. They are highly protective of their family and territory, making them effective guard dogs. 

Bullmastiffs are big, robust, and protective. Although large, they are friendly and caring with their family while vigilantly protecting them from predators.

Italian Cane Corsos are large, faithful, and protective. They're good at protecting their house and family and suspicious of outsiders.

They can make wonderful family pets with the proper care, training and environment, but they may not be ideal for those seeking a traditional guard dog.