The global community faces an array of challenges, such as population growth, food production, natural resource use, and environmental degradation. As such, scientific literacy - the development of scientific understanding and skills for problem-solving and decision-making - is more critical than ever. As such, formal K-16 geoscience teaching and learning will continue to play an important role in cultivating scientific literacy in students, particularly about Earth systems and their human dimensions. One instrument that provides a measure of scientific literacy is The Programme for International Student Assessment (PISA), a triennial international survey designed to evaluate education worldwide by testing the skills and knowledge of 15-year-old students in over 70 countries. In its most recent administration (2015), science was the focal domain of PISA, comprising over half of the assessment and including Earth and Space Science (ESS) as one of three primary content areas assessed. In this presentation, we report findings from analysis of PISA, 2015 science data, which affords an overview of outcomes and processes of secondary (high school) geoscience teaching and learning in international contexts. Specifically, we investigate students’ achievement levels for ESS through country-level comparisons and relationships between these learning outcomes and an array of student-(gender, interest in science, motivation, socio-economic background, etc.) and school-level (science instruction, instructional time, disciplinary environment, etc.) variables as mediators, moderators, and predictors of students’ ESS achievement levels. Study findings show variation in students’ ESS achievement by country and highlight important relationships between these outcomes and other factors, including gender, features of reported science instruction, and student characteristics. These findings leverage a large, international dataset to provide a global perspective on geoscience education. They afford insight into secondary students’ scientific literacy about Earth systems, many of whom will become tomorrow’s undergraduate geoscience majors and non-majors, and therefore have important implications for K-16 teaching and learning about Earth systems.