ABSTRAK Penelitian ini dilatarbelakangi oleh rendahnya pemahaman siswa kelas IV SDN Kutorejo I terhadap materi sejarah perumusan Pancasila. Permasalahan terlihat dari rendahnya hasil belajar siswa, kurangnya partisipasi siswa selama pembelajaran, serta proses pembelajaran yang masih berpusat pada guru. Berdasarkan hasil pra siklus, hanya 12 dari 29 siswa atau 41% yang mencapai ketuntasan belajar dengan nilai ≥75. Penelitian ini bertujuan untuk meningkatkan pemahaman siswa melalui penerapan model pembelajaran Think Pair Share (TPS) berbantuan media Happy Notes. Penelitian menggunakan metode Penelitian Tindakan Kelas (PTK) yang dilaksanakan dalam dua siklus dengan tahapan perencanaan, pelaksanaan, observasi, dan refleksi. Teknik pengumpulan data menggunakan observasi, tes, dan dokumentasi. Instrumen penelitian berupa lembar observasi aktivitas siswa, soal evaluasi, dan penilaian produk Happy Notes. Hasil penelitian menunjukkan bahwa penerapan model TPS berbantuan media Happy Notes mampu meningkatkan aktivitas dan hasil belajar siswa. Persentase ketuntasan belajar meningkat dari 41% pada pra siklus menjadi 69% pada siklus I dan meningkat kembali menjadi 90% pada siklus II. Selain itu, siswa menjadi lebih aktif berdiskusi, berani menyampaikan pendapat, serta mampu menyusun informasi sejarah secara lebih terstruktur melalui media Happy Notes. Dengan demikian, model pembelajaran Think Pair Share (TPS) berbantuan media Happy Notes efektif untuk meningkatkan pemahaman siswa terhadap materi sejarah perumusan Pancasila di kelas IV SDN Kutorejo I. Kata Kunci: Think Pair Share (TPS), Happy Notes, pemahaman siswa, sejarah perumusan Pancasila. ABSTRACT This study was motivated by the low understanding of fourth-grade students at SDN Kutorejo I regarding the history of the formulation of Pancasila. The problem was indicated by low learning outcomes, limited student participation during learning activities, and teacher-centered instruction. Based on the pre-cycle results, only 12 out of 29 students or 41% achieved the minimum mastery criterion score of 75. This study aimed to improve students’ understanding through the implementation of the Think Pair Share (TPS) learning model assisted by Happy Notes media. The study employed Classroom Action Research (CAR) conducted in two cycles consisting of planning, implementation, observation, and reflection stages. Data collection techniques included observation, tests, and documentation. The research instruments consisted of student activity observation sheets, evaluation tests, and Happy Notes product assessments. The results showed that the implementation of the TPS learning model assisted by Happy Notes media improved both student activities and learning outcomes. The percentage of learning mastery increased from 41% in the pre-cycle to 69% in cycle I and further increased to 90% in cycle II. In addition, students became more active in discussions, more confident in expressing opinions, and more capable of organizing historical information systematically through Happy Notes media. Therefore, the Think Pair Share (TPS) learning model assisted by Happy Notes media was effective in improving students’ understanding of the history of the formulation of Pancasila in fourth grade at SDN Kutorejo I. Keywords: Think Pair Share (TPS), Happy Notes, students’ understanding, history of the formulation of Pancasila.