Educators who teach international students English as a second language (ESL) or English speakers teaching English as a foreign language (EFL) in universities in non- English speaking countries in the Asia-Pacific region are often challenged to develop culturally appropriate curriculum for a diverse group of learners. Prompted by educational policy over the past two decades, the technological infrastructure in most universities throughout the world has advanced. Innovative tools for language learning have been developed for computer-assisted instruction. The purpose of the present study was to assess to what extent teachers use multimedia in EFL/ESL university classrooms in relation to the theoretical underpinnings of constructivism as well as Rogers' (1995) theory of diffusion of innovations and adopter categories. Further, the study aimed to ascertain what factors contribute to or discourage teachers' use of multimedia in tertiary level English language teaching classrooms. A mixed- method research design was used and both quantitative and qualitative data were collected. One hundred and seventy-nine English-language teachers from five universities in the Asia-Pacific region were interviewed and data were collected on their use of multimedia. Complex relationships were found among teacher-held educational and cultural values, teaching experience, formal computer professional learning, nationality, institution, region, age, gender, and collaboration with colleagues. Results showed that even with adequate access to hardware, software, technical support and computer professional learning, most teachers in the study made limited use of multimedia in the EFL/ESL classroom. As well, the results indicated that teachers in all three universities in Taiwan used multimedia in the EFL/ESL classroom less than teachers in Australia and in Thailand. Teachers who endorsed constructivist teaching methodologies tended to use multimedia more. Also, teachers with fewer than ten years teaching experience tended to use technology in teaching more. Data showed the use of integrated technology by teachers usually diminished as teachers got older. However, results showed that teachers who engaged in professional learning tended to use multimedia more regardless of age. Future directions in technology integration and recommendations for creating and sustaining a culture of technology at educational institutions are offered. Suggestions for professional development to encourage the integrated use of technology in English language teaching programs are outlined.