Considerable changes to the Lithuanian education system are associated with higher academic achievements, the development of students’ critical thinking and research skills, and sustainable practices of integrated teaching and learning in science and mathematics. It is also acknowledged that STEAM (science, technology, engineering, the arts and mathematics) educational approaches address the objectives of integrated learning and teaching effectively. The same objectives are reflected in all the IB programmes. In the scientific discourse on the use of STEAM in science, there is a lack of research and examples of pedagogical practices with insights into different educational programmes and teachers’ experiences. The qualitative research (semi-structured interview) focuses on the points of view of teachers who implement the international baccalaureate primary years programme (IBPYP), and have a high level of project-based learning experience, of the possibilities of STEAM project implementation (6). The research findings reveal that teachers acknowledge the benefits of STEAM projects in terms of developing students’ research, critical thinking and independent learning skills, while implementing integrated teaching and learning strategies. The informants also recognise the importance of STEAM education in planning and organising integrated mathematics and science lessons.