A fundamental problem in community ecology is to understand when and how interacting species coexist with one another. Coexistence theory, which has been developed over the last decades, is a framework that focuses on examining species’ invasion growth rates in forward models to elucidate mechanisms that enable coexistence. Alongside this theory, new empirical methods to parameterize forward models have been developed. However, these tend to be labor intensive either requiring long-term time series data sets or complex experimental designs. In many cases, genetic data is more readily obtainable. In this talk, I will explore ideas for using multi-species genealogies, inferred from genetic data and in the framework of the coalescent, to inform coexistence.