STEAM education puts professional learning communities on the agenda by requiring teacher collaboration along with disciplinary integrity. In this study, a professional learning community in STEAM education was investigated by observing 49 teachers from different disciplines working in different districts during 16 weeks of interdisciplinary training and their practice with students. Teachers' perceptions of skills teaching self-efficacy, design self-efficacy and perceptions of interdisciplinary teaching were assessed using pre-post tests. The research concluded that the STEAM professional learning community study positively improved teachers' perceptions of skill teaching self-efficacy and interdisciplinary teaching, but was not sufficient to develop design self-efficacy. It was found that teachers' views of practice were positive and that interdisciplinary collaboration contributed to this. In light of the research findings, it was suggested that the use of professional learning communities in STEAM education may be an effective example of the interdisciplinary functioning of hands-on workshops.