ABSTRACT Multidisciplinary learning (ML) contexts have become an integral part of teaching. Since the 2014 curriculum reform in Finland, certain aspects of learning assessment have changed in Finnish basic education. These educational policy reforms and their practical implementation have increased national and international interest in the Finnish curriculum and its approach to learning assessment. This paper explores Finnish primary school (students aged 7–12) teachers’ (PST) perceptions of the significance of learning assessment in basic education, particularly regarding multidisciplinary learning modules. This study implements a phenomenographic research design based on semi-structured interviews (n = 15). The qualitative analysis resulted in five hierarchical outcome categories reflecting the primary school teachers’ perception of significance of learning assessment in a multidisciplinary learning context. The results indicate that primary school teachers’ perceptions of the significance of learning assessment can influence both the variety of assessment, and the teacher/student roles in the design and implementation of assessment. The qualitative findings of this study deepen our understanding of the role of learning assessment in multidisciplinary learning and teaching and support the further development of teacher education in the field of learning assessment. Interactive, comprehensive assessment strengthens quality learning by making learning visible and steering learning towards its goals.