Teachers are expected to keep up to date with challenges and expectations that arise in classroom-based language assessment. This study responds to the call for increased research in the area of language assessment literacy in the context of classroom-based assessment. In particular, our research provides insights into assessment literacy training for in-service teachers of English as a foreign language (EFL). By way of gap analysis based on a questionnaire of 344 EFL teachers in Chinese middle schools, this study found that EFL teachers investigated were nearly at the functional level of classroom-based language assessment literacy (CBLAL), and that they wished to be procedurally and conceptually literate through professional training so as to understand the central concepts of classroom-based language assessment and use their knowledge in practice. The study will shed light on views regarding the assessment literacy topics that are important to be included in in-service EFL teacher training programs.