Ajzen's Theory of Planned Behaviour emphasises that a person's beliefs and competencies are crucial in terms of their behavioural intentions. When transferred to the implementation of a new curriculum, it can thus be hypothesised that teachers’ competencies and beliefs would be the core antecedents of a successful implementation. The context of this study is the new module curriculum ‘Media and ICT (M&I)’ that was introduced in the German-speaking part of Switzerland in 2017. It requires teachers to possess media didactics and technological competencies. This study investigates the current state of teachers’ competencies as well as their beliefs about the new module curriculum M&I. In addition, the relationship between these competencies and beliefs and the teachers’ intention to implement this new curriculum in the classroom is tested. An online survey was administered to 203 teachers. The results show that teachers' competencies only have an indirect effect on their intention to teach M&I when it is mediated by their beliefs (i.e., their readiness to innovate and self-efficacy). Direct effects were found between teachers' readiness and their M&I-related self-efficacy and their intention to implement the new curriculum in their classrooms. The current study contributes to the promotion of digitalisation in the educational field by highlighting the effects of teachers' beliefs and their competencies. Regarding practical relevance, the findings of this study can guide and support the professionalisation of teachers and their initial and further training pertaining to M&I.