This article presents a STEAM education model based on the use of meaningful contexts for the integrated acquisition of key learning outcomes related to different subjects. The model combines inquiry and the use of socio-scientific issues to promote mathematics and science learning along with the development of critical thinking and the integration of cultural and fundamental values. The evaluation of an international teacher professional development programme using a pre/post-test research design shows the programme's impact on secondary school teachers' self-efficacy beliefs, and teaching practices related to the implemented pedagogical model. The qualitative analysis of the teachers' reflections shows that the most appreciated aspects of the programme are transferability to practice, the pedagogical resources offered, the benefits of the model on students' learning, the methodological transformation involved, as well as the opportunity to exchange ideas and practices with colleagues in a professional learning community. These results are of great interest since they reveal a powerful way to promote transformational teacher professional development in the STEAM environment. [Translation from Spanish by Jennifer Martin.]