Society is changing ever faster, and tunnels are complex systems where performance is affected by many different stakeholders. These conditions suggest that safety management needs to be proactive and based on a systems perspective that acknowledges socio-technical theories. Although systems thinking principles are foundational in overarching European regulations and goals, system principles generally don’t affect tunnel fire safety design principles or engineering practice. In the countries investigated in this study, tunnel fire safety management (TFSM) builds on experience-based and risk management-based principles that are optimized independently system by system. This is usually done with limited consideration of how these systems are interconnected and affect the overall tunnel system. The purpose of this paper is to investigate how systems thinking could support existing engineering practice. The work presented in this article is the outcome of a collaboration between fire safety researchers and practitioners from five countries and three continents. Through three workshops, current TFSM principles have been compiled and discussed. It is suggested that tunnel safety regulations be redesigned to strengthen the ability of engineers to work in design teams using systems thinking principles.