The last two decades have seen an unprecedented development of distributed energy resources (DER) all over the world. Distribution System Operators (DSOs) are faced with decisions on how to plan and manage the integration of the DER in their systems in a manner that is both effective and efficient. A foundational component of such planning processes is the ability of the distribution system to “host” the DER. This concept is known as hosting capacity—the maximum DER penetration a distribution network can accommodate without compromising operational reliability or violating technical standards. This chapter explores the methodologies and modelling techniques employed to assess hosting capacity, highlighting the balance between network constraints and DER integration goals. It also examines the evolving regulatory frameworks that shape DSOs’ responsibilities in facilitating DER connections while maintaining system integrity. By framing hosting capacity as an iterative process that integrates diverse data inputs and parameter definitions, this chapter provides insights into strategies for enhancing hosting capacity and supporting the sustainable growth of distributed generation.