Animal models are needed to objectively evaluate the pathogenesis of human periodontal diseases and its various treatment modalities. Selection of the appropriate animal model depends on the similarity of the periodontium and the nature of the disease to that of humans. The more commonly used animal models for studying the pathogenesis of periodontal disease, use of implants and guided tissue regeneration have been dogs and nonhuman primates. Periodontal disease in rodents has not been found to be as closely related to the human varieties. Rats and hamsters are best suited for caries and calculus research. Ferrets may be a promising new model for studying periodontal disease and calculus formation. Variables unique to each animal species are manifested by a wide range of clinical and histopathological features. Different species have distinct diets, habits, life spans, tissue structures, host defense mechanisms and genetic traits. This article describes the diversity seen in animal models used to study microbiological, immunological, and clinical features of periodontal disease and its prevention and treatment.