This research investigates post-primary mathematics teachers’ concerns and feedback around problem-solving and the associated classroom-based assessment (CBA), following significant curriculum reform. Based on a framework of concerns (Hall et al., 1977), semi-structured interviews were conducted with 16 mathematics teachers from across Ireland, representing a range of teaching experiences and school contexts. Initial findings suggest that many teachers feel constrained in attempting any change to their traditional classroom practice due to a lack of confidence and resources in implementing problem-solving in the classroom. Furthermore, teachers directly associate the concentrated nature of the curriculum content and the associated time pressures to a lack of meaningful engagement with the CBA. Teachers’ feedback also emphasises the desire to collaborate with other teachers, both in considering approaches and materials but also in building confidence in their own practice.