This chapter focuses on the simulation of electrostatic discharge (ESD) phenomena. It begins with an introduction to the experimental setup commonly used in ESD testing. In the following section, we present the modeling of ESD generators at both the circuit and EM simulation levels. Since the ESD simulations in the upcoming application example rely on transient co-simulation of the circuit and EM models, we first describe the details of this simulation approach. In the application example, we simulate a contact discharge event to a pin of a USB channel and investigate various modifications to the model. This is followed by a discussion of failure criteria relevant to ESD simulations. The chapter concludes with an introduction to the simulation of ESD air discharge events.