As the price of college tuition continues to rise, higher education institutions and their governing bodies are facing immense pressure to fully understand and explain how tuition, fees, and other sources of revenue are being spent on their campuses. Understanding these expenditures is not only important for the leadership and constituents of the higher education institution, but it is also essential knowledge at the state level, where decisions regarding equitable funding allocations for public colleges and universities are made. While research exists on many different facets of higher education costs, price, and expenditures, this research will focus on one particular area of interest--the direct cost to the university to deliver an education to its students, which on average makes up 34% of the core expenses at public four-year institutions and 39% at private, not-for-profit four-year institutions (National Center for Education Statistics, 2023). While instructional costs are just one piece of the overall expenditures puzzle, they play a crucial role in budgetary conversations and decision-making. Interestingly, even though overall instructional expenditures at public institutions have been increasing over time (Iwamasa and Thrasher, 2019), the cost of delivering instruction per student has remained relatively constant over the last couple of decades (McPherson & Shulenburger, 2010; Hemelt et al., 2021). However, across disciplines and institutions, instructional costs can vary significantly--Middaugh et al. (2003) found that the majority of variation in costs is discipline-specific. The current study builds on previous work that explored cost variation across disciplines within a single institution as well as within-discipline cost variation across numerous institutions. The authors focus specifically on identifying institution--and program-level cost drivers, while also exploring how those drivers differ between disciplines. Any new insights from this study will have important implications for conversations related to higher education funding, especially equitable funding at public colleges and universities.