Given the rising number of biosimilars available across Europe, the US and China and changes in recent access requirements, we aim to compare and contrast the factors that define evolving region-specific patterns in market access for biosimilars. We reviewed publically available secondary sources on recent changes in access requirements, and conducted small-n primary research to compare key access drivers. Several EU markets with coordinated single-payer systems have implemented tenders (France, Italy, Spain, UK), and prescribing quotas (Germany, Italy) securing substantial discounts and high levels of biosimilar penetration. While payers play a significant role in access for biosimilars across all three regions, prescribers have a stronger position as access gatekeepers in Europe. In the US, because of the bigger commercial opportunity, originators have used litigation and contracting to a larger extent to defend their market position vs. biosimilars. However, the Center for Medicaid and Medicare Services has mandated unique biosimilar product identifiers (J-codes) in November 2017, which opens the way for increased competition and contracting with payers. Interchangeability legislation in the US could potentially contribute further to shifting access gatekeeping closer to payers vs. prescribers. In China, reforms aimed at streamlining and simplifying the pricing and reimbursement process for expensive biologics and biosimilars have resulted in the creation of a “price negotiation list” that provides broader nation-wide access and the opportunity to skip burdensome negotiations with China’s 200 provinces in exchange for substantial price discounts. Structural factors and policy decisions determine the evolving biosimilars access environments across the three regions, pointing to a stronger role for payers in a gradually more competitive setting in the US based on recent access-related changes, prescribers playing a stronger access gatekeeper role in Europe with input from patients, and a centralized system in China that increases payer power, incentivizes larger discounts, while providing simplified access.