Assessment is an integral part of the educational process, serving a multifaceted role in guiding instruction and supporting student learning. Among the various functions of assessment, the use of diagnostic assessments is particularly valuable for teachers in understanding their students’ needs, strengths, and weaknesses. By employing diagnostic assessments, educators can gain essential insights into what students know and can do, helping them tailor instruction to meet individual student needs. In this article, we will explore the significance of using assessment as a diagnostic tool, discussing how it enables teachers to enhance student learning. We will delve into the various purposes of diagnostic assessments and their benefits, emphasizing the importance of employing them effectively in the educational setting.