Ecosystem models can be used to understand the cumulative impacts of human pressures and environmental drivers on ecosystem structure and dynamics. Predictive modeling can show how management can influence those dynamics and structures and the ecosystem services these systems provide. Many nations and intergovernmental organizations are advocating for ecosystem-based management, often with a specific emphasis to evaluate various future management strategies. Atlantis is an end-to-end ecosystem model that is well suited for this task and has so far been developed for more than 30 diverse marine ecosystems worldwide. To provide a better understanding of the current modeling work, elicit wider interest, and foster collaboration within the Atlantis community, the first international Atlantis Summit was convened in December 2015. The main outcomes from this workshop included a clearer framework and infrastructure for model development and collaboration; the opportunity to perform common scenarios with a range of Atlantis models to analyze ecosystem responses to environmental and management-based perturbations; and the use of Atlantis as a test case for exploring the performance of single species, multispecies, and trophic food web models at an international level.