The 18^th HLDVT workshop aims to bring together a community of researchers in the areas of design, validation, and test of hardware, software, cyber-physical systems, biological systems, and biochips. The workshop addresses the integration of multiple functions on-chip/in-system at higher levels of design abstraction, and the techniques and methodologies for modeling, analyzing, and validating such systems. In particular, the workshop has become a unique forum for researchers and practitioners to discuss the practical issues associated with validation of extremely large designs.