Assessment is a crucial component of basic education because it serves to identify students' learning needs, development, and learning outcomes. In the Independent Curriculum, assessment is no longer solely oriented towards final results but has become an integral part of the learning process, emphasizing the principles of fairness, objectivity, and education. Issues that still arise in its implementation include the diversity of student abilities, the development of assessment instruments aligned with learning outcomes, and the high administrative burden on teachers. This article aims to describe the concept and principles of basic education assessment standards in the Independent Curriculum, explain their implementation mechanisms, and analyze their implementation and challenges in elementary schools. This research uses a qualitative descriptive approach through documentation, observation, and interviews conducted at Elementary School No. 3 Buduk. The results indicate that assessment standards have been implemented through the planning, implementation, and reporting stages using diagnostic, formative, and summative assessments. Teachers have also implemented various assessment techniques and presented learning outcomes in quantitative and descriptive forms. However, the implementation of assessment still requires strengthening aspects of teacher competency and administrative management to be more effective. Thus, the assessment standards in the Independent Curriculum have supported more meaningful learning, but their optimization still requires institutional support and teacher capacity building.