Building sustainable software systems requires an in-depth understanding about the role that software systems play in our society at a scale and along timeframes that are often difficult to grasp and envisage. We argue that a values ‘first’ software engineering (SE) perspective can offer new insights not only about the human and social aspects that shape SE decision-making processes, but also the potential uses, misuses, and vulnerabilities of complex socio-technical systems afforded by high-level design decisions. While the area of values-based SE has explored means for identifying and making sense of values in the analysis of software production, more effort is required to investigate how values are ultimately instantiated in the architectural structuring of software systems, and the long-term implications of such design decisions. This workshop provides a unique forum where students, researchers, and practitioners working on requirements engineering, software processes, societal aspects of SE, and software sustainability will meet to advance the field of value-based software architectures. We will do so by reporting cases of software design where values tensions may have led to systems failures or to mechanisms that have addressed or mitigated such tensions. The aim is to distill practice-based experiences, methods, and theory into a roadmap for this new and emerging research field.