This study tests the validity of an extended theory of planned behaviour (TPB) to explain teachers' intention to use technology for teaching and learning. Five hundred and ninety two participants completed a survey questionnaire measuring their responses to eight constructs which form an extended TPB. Using structural equation modelling, the results showed that the constructs in the extended TPB were significant in explaining teachers' intention to use technology in their work. Among the constructs in the research model, attitude towards computer use had the largest positive influence on technology usage intention, followed by perceived behavioral control. However, subjective norm had a negative impact on intention. The inclusion of the antecedent variables had also strengthened the ability of the extended TPB model to explain intention. This study contributes to the growing discussions in applying psychological theories to explain behavioral intention in educational contexts.