Inclusive test-based accountability systems are intended to focus attention on the teaching and learning of important knowledge and skills for students with disabilities. Test score inferences to this end are often based on unverified assumptions of curricular alignment, access, and engagement. Focusing on students with disabilities, we discuss key concepts and practices relevant for measuring and facilitating alignment, opportunity to learn (OTL), and student engagement. In conclusion, three recommendations are provided calling for the collection and evaluation of alignment, OTL, and engagement data to support the validity of test score inferences and to inform the design of interventions that improve student OTL and engagement. (Contains 3 figures.)