Teacher learning is of significant importance in mainstream education and a number of attempts have been made to measure the quality of teacher learning across different contexts. The available instruments, however, have been originally developed to assess teachers' perceptions of a single contributive element of teacher learning; therefore, multiple interacting variables which influence the complex process of teacher professional development in English Language Teaching (ELT) contexts have received little attention. This study aimed at developing and validating an instrument whose items are particular to ELT teachers and contexts. To this end, based on a detailed study of the related literature, interviews with ELT practitioners and teacher education professionals, a preliminary theoretical model was proposed. The model was verified and developed into an English Language Teacher Learning Scale. After developing the scale and administering it to 184 ELT teachers, it was validated through both exploratory and confirmatory factor analyses which resulted in a few alterations. This study portrays a more inclusive picture of teacher learning in ELT contexts in terms of factors related to teacher cognition and belief, teacher emotions, teacher motivation, and contextual variables.