Computational thinking (CT) is essential for the young generation in the 21st century to succeed in their learning and daily-life in the digitalized society. It is important for learners in primary and secondary schools to have opportunities to not only meaningfully develop the concepts and practices fundamental to CT competencies, but also for the progress and outcome of their CT development to be assessed in daily learning contexts. The existing literature lacks a universally agreed-upon method of assessment for CT development; and many existing methods for assessment of CT development focus on university learners. This panel aims to address the gap of research discussion about assessments for CT development among young learners in primary and secondary schools. This panel will consist of panel presentations and open-floor discussion about the related experiences, existing challenges, expected dimensions, and possible approaches of CT assessments in primary and secondary schools. This panel can inform the evidence-based evaluation of CT education in the 21st century.