Abstract:As part of an international collaboration to compare large-scale commons, we used the Social-Ecological Systems Meta-Analysis Database (SESMAD) to systematically map out attributes of and changes in the Great Barrier Reef Marine Park (GBRMP) in Australia. We focus on eight design principles from common-pool resource (CPR) theory and other key social-ecological systems governance variables, and explore to what extent they help explain the social and ecological outcomes of park management through time. Our analysis showed that commercial fisheries management and the re-zoning of the GBRMP in 2004 led to improvements in ecological condition of the reef, particularly fisheries. These boundary and rights changes were supported by effective monitoring, sanctioning and conflict resolution. Moderate biophysical connectivity was also important Keeping the 'Great' in the Great Barrier Reef 397 for improved outcomes. However, our analysis also highlighted that continued challenges to improved ecological health in terms of coral cover and biodiversity can be explained by fuzzy boundaries between land and sea, and the significance of external drivers to even large-scale social-ecological systems (SES). While ecological and institutional fit in the marine SES was high, this was not the case when considering the coastal SES. Nested governance arrangements become even more important at this larger scale. To our knowledge, our paper provides the first analysis linking the re-zoning of the GBRMP to CPR and SES theory. We discuss important challenges to coding large-scale systems for meta-analysis.Keywords: Coral reefs, fisheries, Great Barrier Reef, large-scale, marine, socialecological system Acknowledgements: The authors would like to thank the SESMAD team for their support and collaboration, in particular Michael Cox. LE and NB acknowledge funding support from the Australian Research Council Centre of Excellence for Coral Reef Studies. NB also thanks NSERC and SSHRC for financial support. Finally, we are grateful to those who reviewed our paper, including three anonymous reviewers. The arguments developed here are the sole responsibility of the authors.