This study was based on an action research project aiming to investigate how training effectiveness could be influenced by the design of an ICT training program and to explore what factors may affect teachers' engagement in ICT integration. The aim was to understand how ICT training could be designed to meet the needs of a particular group of TESOL teachers and improve their current practice in the context. The main action consisted of a series of ICT training programs in two phases designed for the eight participating TESOL teachers. They shared their experiences and views with me through personal interviews after each phase. The findings emerged from the analysis of interview data and were triangulated with data from observations and informal conversations. The findings show that ICT training has different effects on teachers with different levels of ICT competency. The findings further suggest that the training programs can be more effective if they are tailor-made for teachers in order to cater for their various training needs. Based on the findings, an emergent design model consisting of four basic design features, three specific design features and some design factors was developed. The four basic design features form the basis of the training design while the specific design features and the design factors are to be adjusted according to the particulars of the teachers and their teaching context, making the training programs more effective and connected to real practice. The findings also reveal the importance of some non-design factors on training effectiveness, including hardware provision, technical support and teachers' attitudes towards ICT training and ICT integration, suggesting the need to view the problems from multiple perspectives. These findings, the development of the design model in particular, offer a contribution to our understandings of ICT training for TESOL teachers.