The resources we can provide captive animals are limited in comparison to what they can naturally acquire in the wild. Veterinarians working with captive animals frequently see this result in nutritional deficiencies that can negatively impact the animals. While it may be challenging, if not impossible, to provide captive animals with the same resources they can acquire in the wild, it should not limit us from trying to develop a strategic plan to identify these potential limitations and work towards resolving them. One area that has had some research, albeit limited, is in evaluating the effects of ultraviolet B (UVB) radiation on the synthesis of vitamin D in zoologic species. Much of this focus has been in reptiles, with some work also done with birds and exotic small mammals. When reviewing the evidence, it is obvious that there are differences in the methods used between studies, as well as the results. For example, the overwhelming majority of reptiles synthesize vitamin D following UVB exposure. Exotic small mammals appear to do so too, while birds may not. It is important for us to work out these differences to ensure we are providing these animals in the captive setting with the most appropriate resources. The purpose of this masterclass is to provide a systematic review of the evidence related to our understanding of the role of ultraviolet B radiation for captive reptiles, birds, and small mammals.