Although research findings have emphasized the importance of students being engaged in dialogue and co-construction of science knowledge, implementing the teaching required to promote such engagement is challenging for teachers. Co-construction is crucial not only for students' understanding of science content but also for their familiarity with some of the attributes associated with the nature of science (NOS). Inquiry-based science classroom discourses could facilitate NOS familiarization processes by promoting creativity and collaboration in upper primary school. This article presents findings from a case study of how one teacher created and navigated opportunities for students’ co-construction of science stories in a grade 6 class (age 12) working on the topic “Substances around us”. To examine the classroom dialogue and the teacher’s enablement of students’ co-construction in class, observation data were gathered over seven weeks and analysed using principles indicative of classroom dialogue. Findings show that while opportunities for co-construction were created in science class through for example open-ended questions, the teacher’s use of IRE, complemented with boosted communication for evaluation of student answers, often hampered dialogue and co-construction of novel science stories regardless of how the teaching was organized.