In this issue of Veterinary Clinics: Exotic Animal Practice, guest editors Drs. Sarah Ozawa and João Brandão bring their considerable expertise to the topic of Endocrinology of Zoological Companion Animals. Top experts in the field offer a wide range of clinically relevant articles covering several species, including topics such as ferret insulinomas and adrenal disease; ovarian cystic disease guinea pigs; thyroid disease in rabbits and rodents; hypothalamic pituitary physiology in birds and reptiles; glucose homeostasis and derangement in birds; and many more.