Oncology biological products are some of the most expensive drugs on the market and are a growing financial burden on patients and health-care systems. By 2020, numerous major biological cancer drugs will lose their patent protection allowing follow-on competitors, known as biosimilars, to enter the market. Clinical and regulatory considerations for biosimilars have begun to harmonise in Europe and the USA to help to define and streamline the pathway for biosimilar market authorisation. Yet, substantial international variation still exists in the pricing and market uptake of approved biosimilar oncology drugs. Differences in national postmarket policies for biosimilars might explain these disparities in pricing and uptake. In this Policy Review, policy approaches to competition between biosimilars and originators used by seven European countries—Belgium, France, Germany, Italy, the Netherlands, Norway, and the UK—and the USA are discussed, chosen because these countries represent a variety of postmarket policies and build on conclusions from previous work. We discuss these policies within the context of interchangeability, physician prescribing, substitutability, pharmacist dispensing, hospital financing and tendering, and pricing.