<![CDATA[Mastery of scientific writing requires critical and systematic thinking skills; however, low learning motivation and conventional teacher-centered methods often leave students passive and struggling to complete writing tasks. This study aims to improve the learning motivation of 11th-grade students in class XI E at SMA Muhammadiyah 3 Jember in scientific paper materials through the implementation of Project-Based Learning (PjBL). The study employed Classroom Action Research (CAR) following the Kemmis and McTaggart spiral model across two cycles, each consisting of planning, action, observation, and reflection. The subjects comprised 24 students. Data were collected through structured classroom observations and learning motivation questionnaires covering five indicators. The results indicated that the implementation of Project-Based Learning progressively increased student learning motivation. In Cycle I, the average motivation score was 71.98 (sufficient category), which significantly improved in Cycle II to 82.03 (good category), successfully exceeding the targeted success criterion (). Notable improvements occurred across task persistence, problem-solving interest, tenacity in overcoming difficulties, group collaboration, and active discussion participation. Project-based learning provides meaningful exploration for students to design, write, and present scientific papers. Thus, the Project-Based Learning model is proven effective in enhancing student learning motivation and establishing active, collaborative, and meaningful Indonesian language learning. ABSTRAK Penguasaan materi karya ilmiah menuntut kemampuan berpikir kritis dan sistematis, namun rendahnya motivasi belajar serta dominasi metode konvensional di kelas kerap membuat siswa pasif dan kesulitan menyelesaikan tugas penulisan. Penelitian ini bertujuan untuk meningkatkan motivasi belajar siswa kelas XI E SMA Muhammadiyah 3 Jember pada materi karya ilmiah melalui penerapan model Project-Based Learning (PjBL). Penelitian menggunakan metode Penelitian Tindakan Kelas (PTK) dengan model Kemmis dan McTaggart yang dilaksanakan dalam dua siklus, meliputi tahap perencanaan, tindakan, observasi, dan refleksi. Subjek penelitian berjumlah 24 siswa. Teknik pengumpulan data dilakukan melalui observasi dan penyebaran angket motivasi belajar yang mencakup lima indikator. Hasil penelitian menunjukkan bahwa penerapan Project-Based Learning mampu meningkatkan motivasi belajar siswa secara bertahap. Pada siklus I, rata-rata skor motivasi belajar siswa mencapai 71,98 dengan kategori cukup, kemudian meningkat pada siklus II menjadi 82,03 dengan kategori baik dan telah melampaui indikator keberhasilan tindakan yang ditetapkan (). Peningkatan motivasi terlihat pada aspek ketekunan mengerjakan tugas, minat dalam memecahkan masalah, keuletan menghadapi kesulitan, kerja sama kelompok, serta keaktifan bertanya dan berdiskusi. Pembelajaran berbasis proyek memberi ruang eksplorasi nyata bagi siswa dalam merancang, menyusun, dan mempresentasikan karya ilmiah. Dengan demikian, model Project-Based Learning terbukti efektif dalam meningkatkan motivasi belajar siswa dan mewujudkan pembelajaran bahasa Indonesia yang aktif, kolaboratif, serta bermakna. ]]>
