Standardized foreign language assessments are increasingly used for high-stakes decisions affecting teachers and students alike. Therefore, understanding their influence on instruction, and connecting teachers’ practices to outcomes, is critical to support evidence-based efforts to increase students’ language development. In my dissertation, I investigate the interplay between assessment and instructional practices in an urban K-12 world language program. Findings have implications for educators and policymakers regarding effective practices for teaching, learning, and assessment of foreign languages.