Feedback is dependent on how it is interpreted and used. The present study aimed to explore Swedish primary-school teachers' and students' shared concerns regarding classroom feedback interaction. 13 teachers and 23 students (7-9 years old) were interviewed. A grounded theory design was employed for coding and analysis. According to the findings, teachers' and students' mutual main concern was to construct clarity regarding what the other communicated. Both strived to construct clarity concerning conditions that they had to adapt to, from aspects as trustworthiness and understanding. The study contributes with an illustration of the relational aspect of classroom feedback in primary school.