Increasing demand for sustainable energy has led to research and development on the cultivation of diverse plant species for biomass production. To support the research and development required to domesticate and cultivate crops for bioenergy, we developed the Biofuel Ecophysiological Traits and Yields database (BETYdb). BETYdb is a centralized open-access repository that facilitates organization, discovery, and exchange of information about plant traits, crop yields, and ecosystem functions.