Recently growth-based approaches to accountability have received considerable attention because they have the potential to reward schools and teachers for improving student performance over time by measuring the progress of students at all levels of the performance spectrum (including those who have not yet reached proficiency on state accountability assessments). While the use of growth in accountability holds promise for students with disabilities, measuring changes over time in their academic performance is complex. This paper summarizes models and approaches that use individual student test scores from multiple years for 3 different purposes: determination of adequate yearly progress under the federal accountability system, research on individual growth trajectories, and evaluation of the contribution of teachers and schools to student learning. Practical challenges in measuring and modeling growth for students with disabilities are then discussed. Finally, 3 areas in need of research on the measurement of growth from large-scale annual accountability assessments are identified and described: testing accommodations, test difficulty, and understanding the longitudinal characteristics of the population of students with disabilities. (Contains 4 tables, 1 figure and 4 notes.)