We examined the degree to which content of states' writing standards and assessments (using measures of content range, frequency, balance, and cognitive complexity) and their alignment were related to student writing achievement on the 2007 National Assessment of Educational Progress (NAEP), while controlling for student, school, and state characteristics. We found student demographic characteristics had the largest effect on between-state differences in writing performance, followed by state policy-related variables, then state and school covariates. States with writing tests that exhibited greater alignment with the NAEP writing assessment demonstrated significantly higher writing scores. We discuss plausible implications of these findings.