<p>Meeting students’ diverse learning needs and skills in contemporary classrooms has become a central concern in education today. Consequently, the current study aimed to identify secondary school English language teachers’ perceptions of and instructional strategies in mixed-ability classes (MACs). We adopted a concurrent mixed-method design to address the objectives of the study. We selected 67 teachers for the questionnaire survey and six teachers for classroom observations via systematic random sampling. We also selected five teachers for unstructured interviews. We employed a Single-Sample t-test, one-way analysis of variance, Tukey post hoc analysis, and one-sample binomial test to analyze the quantitative data. In addition, we used an inductive approach to organize and analyze the unstructured interview data. The teachers in the sample schools demonstrated conceptual and procedural awareness of MACs, although they had partially implemented MAC instructional strategies. The study highlighted the need for education departments of the local government to provide awareness-raising training on the conceptual and procedural aspects of MACs and to provide hands-on training on the pedagogical skills of teaching MACs for English language teachers in the sample schools.</p>