Unlike new drug development where superiority over an active comparator or placebo often has to be proven, biosimilar development focuses on showing similarity of the proposed biosimilar to an already approved reference product. This affects the statistical aspects of clinical trials including choice of study design, endpoints, and analyses performed. In addition, there is a greater focus on margin justification and missing data imputation for efficacy. This article provides an overview of the statistical principles inherent to biosimilar development.