<![CDATA[This research was motivated by the difficulties faced by seventh-grade students at SMPN 1 Lubuk Sikaping in understanding the classification of living things due to the heavy memorization of scientific terms and the limitations of existing student worksheets (LKPD). This study aimed to develop a valid, practical, and effective LKPD based on the Plomp development model for the topic of Classification of Living Things. Data collection instruments included needs analysis questionnaires, validation sheets, practicality questionnaires, and assessment instruments for attitudes and knowledge. Data were analyzed using descriptive percentages. The results of the preliminary investigation stage indicated a high demand for innovative teaching materials. In the prototyping stage, the LKPD was evaluated as highly valid (94.55%) by experts and highly practical through one-to-one trials (90.28%) and small group trials (89.02%). In the assessment stage, the LKPD proved highly user-friendly for teachers (96.98%) and students (87.86%), and demonstrated excellent effectiveness in the attitude (97.43%) and knowledge (100%) domains. Based on these findings, the developed LKPD meets the quality criteria for educational materials and is highly recommended for optimizing students' conceptual understanding and learning outcomes. Abstrak. Penelitian ini dilatarbelakangi oleh kesulitan peserta didik kelas VII SMPN 1 Lubuk Sikaping dalam memahami materi klasifikasi makhluk hidup karena banyaknya hafalan istilah ilmiah dan keterbatasan LKPD yang digunakan. Penelitian ini bertujuan untuk menghasilkan LKPD berbasis model pengembangan Plomp pada materi Klasifikasi Makhluk Hidup yang valid, praktis, dan efektif. Instrumen pengumpulan data meliputi angket analisis kebutuhan, lembar validasi, lembar kepraktisan, serta instrumen penilaian sikap dan pengetahuan. Data dianalisis secara deskriptif persentase. Hasil penelitian tahap investigasi awal menunjukkan tingginya kebutuhan akan bahan ajar inovatif. Pada tahap pembentukan prototipe, LKPD dinilai sangat valid (94,55%) oleh ahli dan sangat layak/praktis melalui uji one-to-one (90,28%) serta small group (89,02%). Pada tahap penilaian, LKPD terbukti sangat mudah digunakan oleh guru (96,98%) dan peserta didik (87,86%), serta memiliki efektivitas yang sangat tinggi pada aspek sikap (97,43%) dan aspek pengetahuan (100%). Berdasarkan temuan ini, LKPD yang dikembangkan memenuhi kriteria kelayakan kualitas bahan ajar dan sangat direkomendasikan untuk digunakan dalam mengoptimalkan pemahaman konsep serta hasil belajar peserta didik pada materi klasifikasi makhluk hidup.]]>
