<![CDATA[Affective assessment is an important component of learning because it provides information about students' attitude development that cannot be fully represented by cognitive assessment results alone. Preliminary observations at SD Negeri 075027 Silima Omo indicated that attitude assessment was still based on general observations and was not supported by a structured instrument with clear operational indicators. This study aimed to develop an affective assessment instrument for third-grade IPAS learning that met validity and practicality criteria and received positive responses from teachers as users. The study employed a Research and Development (R&D) method using the 4D model, consisting of the define, design, develop, and disseminate stages. The participants consisted of three expert validators, namely material, language, and evaluation experts, one third-grade teacher, and 23 third-grade students at SD Negeri 075027 Silima Omo. The developed product consisted of a teacher observation sheet, attitude scale, self-assessment sheet, and peer-assessment sheet covering five affective aspects: curiosity, cooperation, responsibility, honesty, and scientific attitude. The results of the second-stage validation showed average scores of 3.88 from the material expert, 3.78 from the language expert, and 3.90 from the evaluation expert, all of which were categorized as highly feasible. The second-stage practicality test obtained a percentage of 97.5%, while the teacher's response to the use of the instrument also reached 97.5%, both categorized as very good. Therefore, the developed affective assessment instrument met the criteria of validity and practicality and received a positive response from the teacher, making it feasible for use in third-grade IPAS learning within the context of the study. ABSTRAK Penilaian afektif merupakan bagian penting dalam pembelajaran karena memberikan informasi mengenai perkembangan sikap peserta didik yang tidak dapat direpresentasikan melalui hasil penilaian kognitif saja. Hasil observasi awal di SD Negeri 075027 Silima Omo menunjukkan bahwa penilaian sikap masih dilakukan berdasarkan pengamatan umum dan belum didukung instrumen yang terstruktur dengan indikator operasional yang jelas. Penelitian ini bertujuan mengembangkan instrumen penilaian afektif pada mata pelajaran IPAS kelas III yang memenuhi kriteria valid dan praktis serta memperoleh respons positif dari guru sebagai pengguna. Penelitian menggunakan metode Research and Development (R&D) dengan model 4D yang meliputi tahap define, design, develop, dan disseminate. Subjek penelitian terdiri atas tiga validator ahli, yaitu ahli materi, ahli bahasa, dan ahli evaluasi, satu guru kelas III, serta 23 peserta didik kelas III SD Negeri 075027 Silima Omo. Produk yang dikembangkan terdiri atas lembar observasi guru, skala sikap, lembar penilaian diri (self-assessment), dan lembar penilaian antarteman (peer-assessment) yang memuat lima aspek afektif, yaitu rasa ingin tahu, kerja sama, tanggung jawab, kejujuran, dan sikap ilmiah. Hasil validasi tahap II menunjukkan skor rata-rata ahli materi sebesar 3,88, ahli bahasa sebesar 3,78, dan ahli evaluasi sebesar 3,90, yang seluruhnya berada pada kategori sangat layak. Uji kepraktisan tahap II memperoleh persentase 97,5%, sedangkan respons guru terhadap penggunaan instrumen memperoleh persentase 97,5%, keduanya berada pada kategori sangat baik. Dengan demikian, instrumen penilaian afektif yang dikembangkan memenuhi kriteria valid dan praktis serta memperoleh respons positif dari guru dan layak digunakan pada pembelajaran IPAS kelas III sesuai dengan konteks uji coba penelitian.]]>
