Policy-makers are increasingly turning to behavioral science for insights about how to solve pressing challenges (e.g., encouraging vaccination, reducing energy consumption). However, the efficacy of behavioral science interventions are typically evaluated independently in different samples examining different outcomes over different time intervals, which makes it difficult to compare their relative effectiveness. Most studies are also conducted on small samples in a laboratory setting, further limiting their potential to inform policy. The Behavior Change for Good Initiative has developed a novel, collaborative approach to combat these issues in behavioral science—the “megastudy.” A megastudy is a large field experiment in which many sub-studies are tested simultaneously on the same objective outcome, allowing for apples-to-apples (and dollars-to-dollars) comparisons across many different interventions developed from multiple disciplines. We will share fresh insights that this new approach to applied behavioral science research has generated to date and discuss recommendations, limitations, and promising future directions.