Article in press; Available online 20 September 2011 ; Periodontal disease (PD) refers to a group of inflammatory diseases caused by bacterial plaque in the periodontium and ranges from an early stage (gingivitis) to an advanced stage (periodontitis). It is a multifactorial disease that results from the interaction of the host defence mechanisms with the plaque microorganisms. Early detection, diagnosis and treatment are essential in the control of this disease. PD has an enormous impact on human and veterinary medicine due to its high prevalence. The most common animal PD models use dogs and non-human primates, although other animals (rats, mice, hamsters, rabbits, miniature pigs, ferrets, and sheep) have also been employed. Dog models have contributed significantly to the current understanding of periodontology. The most important clinical aspects of canine PD are considered in this review and the various animal models are examined with an emphasis on the role of the dog as the most useful approach for understanding human PD and in the development of new therapeutic and preventive measures.