The theory of planned behaviour (TPB) claims that behaviour can be predicted by behavioural intention and perceived behavioural control, while behavioural intention is a function of attitude towards the behaviour, subjective norm, and perceived behavioural control. This study aims at providing explanation and prediction of teachers' inclusive education intentions and behaviour under TPB. The main components of TPB were implemented in a survey of 841 teachers from Hong Kong schools in the context of inclusive education. The structural equation modelling results show that TPB fitted the data well (?[superscript 2]/df?=?2.84; RMSEA?=?0.054; GFI?=?0.92; CFI?=?0.92; and TLI?=?0.91). Identified attributes, including teachers' attitude towards inclusive education, feeling social pressure from important others to carry out inclusive education, and confidence on professional training for involved staff, were found to exert significant predictive power on teachers' intention to implement inclusive education. This intention, together with the confidence on professional training for involved staff, predicts their actual inclusive practice. Teachers' perception of social pressure and adequacy of professional training greatly contribute to predict their intention and behaviour towards inclusive education, respectively. TPB appears to be a sound theoretical framework for understanding teachers' inclusive practice. The results have strong implications for teacher empowerment and professional training in inclusive education.