Using state-representative surveys, we investigated how familiar Texas, Ohio, Kentucky, and Massachusetts principals are with their state's K-12 standards, as well as the strength of their policy environments, using a policy attribute theory. We found relatively high levels of buy-in toward the idea of standards but only a general familiarity with the standards themselves. Principals are least familiar with the standards in mathematics, and high school principals are significantly less familiar with their state's standards than elementary principals. Using ordinary least squares (OLS) regression, we found no relationship between student proficiency and principal familiarity, but we did find a significant and positive relationship between stronger policy environments and greater familiarity among principals in Texas. [This is the online version of an article published in "Teachers College Record."]