Biosimilar insulins, also known as follow-on biologics, are modifications of an originator insulin that are intended to be clinically equivalent to the licensed product. For injectable insulins, or other peptides used in the management of diabetes, regular use of an insulin pen injector or other device to administer therapy is part of the patient’s self-management regimen. By definition, the biosimilar product should have comparable pharmacokinetic and pharmacodynamic properties to the reference product. However, the device is the initial interaction for the patient rather than the product contained within. We consider the regulatory aspects of insulin device development. The options for manufacturers bringing a biosimilar insulin to market, including whether to outsource development of delivery devices, are explored. The structure of a device development program is outlined and issues of accuracy, safety, ease of use, and attractiveness of modern insulin delivery devices are discussed.