Implementation of science curriculum materials has been a fundamental challenge in science education for decades. Policy researchers have argued that alignment of standards, curriculum, and assessment are the key to supporting implementation. This paper focuses on teachers' perceptions of curricular alignment and on curriculum implementation using empirical data from a statewide systemic inquiry science reform effort targeting students from kindergarten to eighth grade. We find that the success of alignment policies depends on teachers' construal of the relationship between standards and curriculum materials and on allocation of time for planning at the school level. (Contains 4 tables, 2 figures and 1 footnote.)