This paper explores drug and alcohol policies at Tribal Colleges and Universities (TCUs). A research team conducted a needs assessment of Alcohol and Other Drug (AOD) use and policies in 27 TCUs, surveying key informants on perceived AOD prevalence. Student body size did not affect levels of AOD training or treatment. Larger TCU size increased the likelihood of on-campus housing, which increased the prevalence of zerotolerance policies and greater access to AOD services. Reservation policies, local resources, and cultural practices did not appear to affect TCU AOD policies. Designed properly, these policies can support desirable academic outcomes for TCU students.