It is widely acknowledged that the use of assessment to enhance teaching and improve student learning is grounded in a strong research evidence base. Educational institutions around the world are encouraging teachers to implement the principles of assessment for learning (AfL) to improve their classroom practices and hence, student achievement. However, many EAL teachers in Australia report dissatisfaction with their levels of assessment literacy, yet there are few effective tools to evaluate their knowledge and skills. Drawing upon the principles of assessment for learning and curriculum innovation and change, this paper reports on the development of a standards-based framework for describing and evaluating ESL teachers' assessment literacy, to be be used as the basis for developing a more effective assessment literacy program. The framework has undergone several rounds of expert validation and an application of Rasch latent trait theory and factor analysis resulting in the identification of five emerging domains which specify the job roles of ESL teachers in assessment. These include ESL teachers being assessors, pedagogy experts, motivators, teacher learners and stakeholder partners. Each of these domains comprises certain capabilities and indicators of practice. This paper reports on the use of this framework in the Tools to Enhance Assessment Literacy (TEAL) of Teachers of English as an Additional Language (TEAL) project as both a tool for self-evaluation and professional development.