We examined changes in teachers' beliefs regarding developmentally appropriate practice (DAP) in 2000, 2003, 2006, and 2009 using data from the Head Start Family and Child Experience Survey. In addition, we examined how teacher education, credentials, and professional experience relate to beliefs about DAP and explored how these relationships differ by cohort. We also explored teachers' reports of time spent in math and literacy focused activities. Findings indicate that after 2003, developmentally appropriate beliefs decreased significantly, while developmentally inappropriate beliefs increased. Results also showed significant increases in the frequency of literacy activity across the decade, while the frequency of math activity was more consistent. Despite these changes, teachers with more education consistently held the most appropriate beliefs. These findings indicate that teacher education may buffer against influences of pushed down curricula and increased accountability. This study also illustrates that policies at the national level have the potential to impact children's day-to-day classroom experiences.