A key aim of sustainable development is the joint achievement of prosperity, equality, and environmental integrity: in other words, material living standards that are high, broadly -distributed, and low -impact. This has often been called the triple bottom line. But instead, what if there is a trilemmathat inhibits the simultaneous achievement of these three goals? We analysed international patterns and trends in the relationships between per -capita gross national income, the Gini coefficient for income distribution, and per -capita ecological footprint from 1995 to 2017, benchmarking them against thresholds from the existing literature. A dynamicanalysis of the trajectories of 59 countries and a staticanalysis of a larger sample of 140 countries found that none met the triple bottom line, and that instead there were widespread tradeoffs among the three indicators. These tradeoffs, leading to divergent national trajectories and country clusters, show that common pair -wise explanations such as Kuznets Curves do not adequately capture important development dynamics. In particular, while only a few countries simultaneously met the thresholds for prosperity and equality on the one hand and equality and environment on the other, none did for prosperity and environment. Moreover, inequality likely makes resolving this critical tradeoff more difficult. Our findings suggest that mitigating the sustainability trilemma may require countries - especially those that are already prosperous - to prioritize economic redistribution and environmental stewardship over further growth.