Over the past century, wildland fire management has been core to the mission of federal land management agencies. In recent decades, however, federal spending on wildfire suppression has increased dramatically; suppression spending that on average accounted for less than 20 percent of the USFS’s discretionary funds prior to 2000 had grown to 43 percent of discretionary funds by 2008 (USDA 2009), and 51 percent in 2014 (USDA 2014). Rising suppression costs have created budgetary shortfalls and conflict as money “borrowed” from other budgets often cannot be paid back in full, and resources for other program areas and missions are subsumed by suppression expenditures (Thompson et al. 2013). Significant policy making over the past 15 years has been designed, at least in part, to address these issues and temper wildfire costs. Effective political efforts and strategies to control public spending on suppression rely on a thorough and comprehensive understanding of the drivers of suppression costs and recent trends. Currently, scholars and policymakers have little understanding or agreement on the diversity of drivers behind wildfire suppression costs, how drivers vary in different situations, or what specific tactics or approaches might best reign in rising costs. There is great variability in costs between comparable wildfires in the same season, as well as between comparable fire seasons. Problematically, much of this variation is unexplained by frequently noted drivers. As speculation and scrutiny around potential drivers has increased, so too has a growing body of scholarly literature investigating the correlates and influences driving suppression costs. A more comprehensive understanding of the full suite of factors affecting suppression costs can inform how land management agencies can best leverage limited resources for wildfire management, and how budget allocations could more accurately accommodate annual suppression costs. This working paper gathers together existing scholarly literature on wildfire suppression cost drivers. The purpose of the paper is to provide an overview of the diversity of drivers examined in scholarly literature that may influence suppression costs; be a resource for documenting the growth, parameters, and directions in this field of research; and serve as a central collection annotating this literature to date.