Biological veterinary medicinal products (“biologics”) are an innovative and fast-growing component of the veterinary pharmaceutical market. Biologics provide veterinarians with valuable new treatments to improve the health and welfare of their animal patients by addressing unmet need, while providing value to pet owners. Biologics differ from traditional pharmaceuticals because they are produced by, or extracted from, a biological source and therefore may have different regulatory considerations. Of note, in the U.S., animal biologics are subject to the regulatory oversight of the U.S. Department of Agriculture (USDA) rather than the U.S. Food and Drug Administration (FDA), which regulates other therapeutic products, including animal drugs. In contrast, in the UK and EU, biologics do not have separate regulatory frameworks or regulators and there are clear approval routes for biosimilars. In this article, we provide a practical overview of the regulatory considerations for approval and commercialisation of biosimilars in the U.S., EU, and UK