Penelitian ini bertujuan mengembangkan media pembelajaran berupa video animasi berbasis model Flipped Classroom pada materi barisan aritmatika serta menguji kevalidan, kepraktisan, dan keefektifannya dalam meningkatkan pemahaman konsep matematis siswa. Metode penelitian menggunakan Research and Development (R&D) dengan model 4-D (Define, Design, Develop, dan Disseminate). Produk yang dihasilkan berupa RPP, LKPD, instrumen tes, dan video animasi. Validasi dilakukan oleh ahli materi dan media, sedangkan uji coba dilakukan pada kelompok kecil (6 siswa) dan kelompok besar (36 siswa) di SMAN 1 Selesai. Hasil validasi memperoleh skor rata-rata 83,3% (sangat valid). Uji coba kelompok kecil memperoleh skor 86,7% dan kelompok besar 83,3%, sedangkan respon guru 84%, sehingga perangkat termasuk kategori “sangat praktis”. Keefektifan ditunjukkan melalui ketuntasan klasikal 86%, dengan 31 dari 36 siswa mencapai nilai ≥ 85 sesuai KKM. Dengan demikian, media video animasi berbasis Flipped Classroom dinyatakan valid, praktis, dan efektif, sehingga dapat menjadi alternatif media pembelajaran untuk meningkatkan pemahaman konsep matematis siswa. ABSTRACT This study aims to develop learning media in the form of animated videos based on the Flipped Classroom model for arithmetic sequences and to test its validity, practicality, and effectiveness in improving students' understanding of mathematical concepts. The research method used Research and Development (R&D) with the 4-D model (Define, Design, Develop, and Disseminate). The products produced were lesson plans, student worksheets, test instruments, and animated videos. Validation was carried out by subject matter and media experts, while trials were conducted on a small group (6 students) and a large group (36 students) at SMAN 1 Selesai. The validation results obtained an average score of 83.3% (highly valid). The small group trial obtained a score of 86.7% and the large group 83.3%, while the teacher response was 84%, so the tools were categorized as “very practical”. Effectiveness was demonstrated through a classical completion rate of 86%, with 31 out of 36 students achieving a score of ≥ 85 according to the minimum passing grade. Thus, the Flipped Classroom-based animated video media was declared valid, practical, and effective, making it an alternative learning media to improve students' understanding of mathematical concepts.