This study examined teachers' internet use behaviour for professional development using the theory of planned behaviour. Data for this study were collected via a survey of 221 teachers who completed self-reported measures of attitude, subjective norm, perceived behavioural control, intention, and behaviour. The planned behaviour model was specified and tested using structural equation modelling. The result of the study provides partial support for the adequacy of the theory of planned behaviour for predicting and understanding internet use behaviour for teachers' professional development. There was a strong link between behavioural intention and internet use behaviour. Intention was predicted significantly by perceived behavioural control and attitude toward the behaviour. (Contains 2 figures and 3 tables.)