<![CDATA[Diagnostic assessment enables teachers to identify students’ prior knowledge, understanding, learning readiness, and learning difficulties before instruction. This study aims to identify the forms of diagnostic assessment implemented in Indonesian language learning, examine its strengths and weaknesses, and explore its impact on students’ understanding and learning engagement. This study employed a descriptive qualitative approach. Data were collected through observations, structured interviews, and documentation involving the fifth-grade homeroom teacher and ten student informants at SD Negeri 076688 Hiligawoni. Six classroom observations were conducted from January 30 to February 28, 2026. Data were analyzed through data reduction, data presentation, conclusion drawing, open coding, and thematic construction. Data validity was established through source, technique, and time triangulation and member checking. The findings show that diagnostic assessment was primarily implemented as cognitive diagnostic assessment through oral questions, written tests, and assignments. The assessment identified students’ prior understanding, learning readiness, and difficulties and provided a basis for additional explanations or enrichment. Its strengths included increased student participation and enthusiasm and improved identification of learning needs. Its weaknesses included some students’ lack of confidence in answering questions and the additional time required, which sometimes reduced time for subsequent materials. The findings indicate that diagnostic assessment positively supported students’ understanding and learning engagement through follow-up instruction. The study recommends continuing diagnostic assessment while incorporating non-cognitive aspects and improving implementation efficiency.]]>
