Elementary and Secondary Education Act (ESEA) flexibility requires states to develop and implement teacher effectiveness measures that consider student assessment results, including assessment results for students with disabilities participating in general and alternate assessments. We describe how alternate assessment results for students with significant cognitive disabilities could appropriately be used in teacher effectiveness measures. In addition, we discuss the unique parameters faced by teachers serving students with significant cognitive disabilities that may warrant a multiple measures approach to evaluating teacher effectiveness. Using one of the two national initiatives presently developing alternate assessments based on the Common Core State Standards as an example, we describe how these new assessments might be applied in measuring teacher effectiveness. Finally, we offer implications for both policy makers and practitioners in measuring teacher effectiveness for teachers serving students with significant cognitive disabilities participating in alternate assessments.