In 2015, the United States Food and Drug Administration (FDA) approved the first biosimilar, filgrastim-sndz, a biosimilar of the granulocyte colony-stimulating factor filgrastim. Since that time, the FDA has approved four additional biosimilar tumor necrosis factor α inhibitors, and, in May 2017, the Oncology Drug Advisory Committee voted in favor of approval of an epoetin alfa biosimilar. The patents of several widely used biologic cancer therapies (including trastuzumab, rituximab, bevacizumab, cetuximab, and pegfilgrastim) are recently expired or due to expire in the near future, so the introduction of biosimilars into the oncology treatment armamentarium is imminent. However, their arrival also will introduce challenges, including pharmacy and supply chain management and the need for education of clinicians and patients about the efficacy and safety of these agents. These considerations, along with an overview of biosimilars in the oncology pipeline, will be discussed in this review.