This qualitative study has attempted to explore the challenges encountered by the grade VI students during the implementation of the New Curriculum Framework-2021. This competency-based new curriculum which emphasizes on innovative pedagogical approaches has been in implementation for grade VI and VII throughout Bangladesh since January 2023. A case study on Khulna University School has been carried out to conduct this study. The research questions of this study focus on the challenges relevant to teaching-learning and assessment and how those are affecting students’ learning. To answer the questions classroom observations and semi-structured interviews of the students as well as the teachers were done. Then obtained data were analyzed by using thematic analysis technique from which major themes emerged. This Study finds that the students are facing a number of challenges including difficulties in understanding instruction and assessment criteria, lack of active participation, insufficient class duration and physical facility, irregular feedback etc. This study also finds that both the students and teachers have claimed that as they were not adequately prepared for a full scale implementation, the mentioned challenges are hampering learning by creating learning gaps and widening parental concerns along with financial issues. The findings have implications for the government, policymakers, curriculum developers, school authority, teachers and other stakeholders so that they can minimize the challenges that the students are facing. This study recommends that bottom-up approach, adequate preparatory time, effective curriculum dissemination, teacher training programs, improved learning environment are required for successful implementation of the new curriculum.