Throughout their careers, Oran Young and Elinor Ostrom had an ongoing and unresolved discussion on whether any of her design principles of local institutions associated with the successful and long-enduring management of common resources could be upscaled to the international level. Using qualitative comparative analysis and fixed-effects regression models with data from the International Regimes Database (Breitmeier, Young, & Zürn, 2006) I test whether four of her principles are associated with improved performance in 38 multilateral environmental treaties.