Exotic companion mammals represent a branch of veterinary medicine with important implications in dentistry. The standard dental nomenclature and systems have not been applied in detail in these species and are unfamiliar to many veterinarians. Selected species including rabbits and rodents have anatomic and physiologic features affecting terminology and numbering. Marsupial species dentition is different from placental mammals, complicating the use of the modified Triadan system. This lecture will describe, illustrate, and compare 4 numbering systems currently used for most common exotic mammal species and proposes a modification for application to marsupials.