As an innovative educational tool, e-textbooks has gained wide interest -- especially with the growth of e-learning. As with any new technology, understanding how users adopt these technologies is still unclear. In the study reported on here we proposed a theoretical model shaping the determinants of teachers' attitude toward e-textbooks. Specifically, we identified three contextualised factors (ease of use, usefulness, and concerns) as the factors of adopting e-textbooks. In addition, we examined teachers' use of e-textbooks. A mixed-methods research design was used in which quantitative and qualitative data were collected and analysed. The results show that teachers held positive attitudes toward using e-textbooks in their teaching and used them as instructional aids. The results might inform education decision-makers who are planning to integrate e-textbooks into their schools in line with digital transformation and the knowledge society.