Advanced therapy medicinal products (ATMPs) are an innovative group of medicines that have great potential to treat or even cure diseases with a high unmet medical need. ATMPs encompass gene therapy medicinal products, somatic cell therapy medicinal products, tissue-engineered products, and combined ATMPs (i.e., a combination with a medical device). ATMPs are considerably more complex than more conventional medicines that contain, for example, small molecules or monoclonal antibodies. Differences lay, among others, in the mechanisms of action, raw materials, such as live human cells and tissues, intended functions, manufacturing processes, and quality assurance. In addition, the drug developer landscape is different, with a greater involvement of academic developers and small- and medium-sized enterprises, which often lack awareness of regulatory and economic requirements and processes. Through a combination of these and other factors, only few ATMPs so far have reached routine clinical practice. In this chapter, the regulatory and health technology assessment (HTA) processes for ATMPs in the European Union (EU) are explored, including how they may differ from processes for non-ATMPs. In addition, four key challenges in the regulation and HTA of these innovative medicines are discussed, followed by a reflection on postreimbursement aspects that may affect sustainable patient access to ATMPs, and a perspective on the future. As such, this chapter is of relevance to everyone who is interested in how regulatory and HTA processes contribute to patient access to ATMPs in the EU.