Several studies have been undertaken to develop instruments to measure English teachers' TPACK, but few studies have measured English teachers' TPACK to develop meaningful relationships among technology, content, and pedagogy in the context whereby literacy should be associated with a range of semiotic modes beyond the written language. The interactions with a wider range of texts across modes, media and contexts point to the need for an instrument that can measure English teachers' TPACK in the context of teaching multimodal literacies. In this study, we investigated what factors and items were necessary for examining pre-service teachers' TPACK in multimodal literacy teaching. The proposed TPACK instrument was validated with 220 pre-service teachers across three institutions in Indonesia, China, and Australia. The study shows that the proposed eight-factor instrument generally expressed acceptable validity and reliability and was appropriate for assessing pre-service teachers' TPACK for multimodal literacies. Implications and further research are discussed with the aim of equipping pre-service teachers with the capabilities to integrate content, pedagogy, technology and understand the complex interdependence of contextually bound factors that influence their classroom readiness in teaching multimodal literacies.