Earth System Governance (ESG) is a broadly formulated network of research agencies and governance bodies which aims to integrate science with policy and governance as a means of managing environmental change. Taking into consideration the broader context of ongoing attempts to define optimal solutions for major contemporary challenges, a comparison of ESG and science diplomacy focuses on four commonalities. The purpose of this comparison is to explore mutual learning opportunities because both strands of enquiry aim at addressing the global challenges in a comprehensive manner through tailored relations between science or research and policy or diplomacy. ESG and science diplomacy share an interest in exploring the top-down and bottom-up dynamics of multi-level governance, circulation of ideas, terms, including the expansion of their meanings, experimentation outside the existing institutional structures, as well as anticipation of future developments. A primary focus on Europe articulates areas where ESG and science diplomacy may find thematic intersections for mutual learning.