Abstrak: Penelitian ini bertujuan untuk 1) mengetahui validitas media pembelajaran Big Book 2) mengetahui praktikalitas media pembelajaran Big Book 3) mengetahui efektifitas media pembelajaran Big Book. Jenis penelitian yang digunakan R&D dengan model pengembangan 4D yaitu Define, Design, Develop, dan Disseminate. Subjek penelitian ini sebanyak 25 siswa/i Kelas IV-B SD Negeri 067690 Medan Johor. Teknik pengumpulan data menggunakan angket, tes, dan dokumentasi. Teknik analisis data menggunakan pendekatan kualitatif dan kuantitatif. Hasil penelitian ini persentase ahli materi 96,17% dinyatakan “Sangat Layak” dan persentase validasi ahli media 89,43 % dinyatakan “Sangat Layak”. Praktikalitas dengan persentase 98% dinyatakan “Sangat Praktis”. Efektivitas N-Gain skor diperoleh sebesar 0,76 atau g>0,7 dan N-Gain Skor Persen 76,01% dinyatakan “Efektif”. Dapat disimpulkan media pembelajaran Big Book yang dikembangkan peneliti sangat layak, sangat praktis, sangat efektif digunakan pada Tema 6 Cita-citaku Sub Tema 2 Hebatnya Cita-Citaku Pembelajaran 2 Kelas IV SDN 067690 Medan Johor T.A 2022/2023. Kata Kunci: Pengembangan, Big Book, 4D. Abstract: This study aims to 1) determine the validity of Big Book learning media 2) determine the practicality of Big Book learning media 3) determine the effectiveness of Big Book learning media. The type of research used is R&D with the 4D development model, namely Define, Design, Develop, and Disseminate. The subjects of this study were 25 students in Class IV-B of SD Negeri 067690 Medan Johor. Data collection techniques using questionnaires, tests, and documentation. Data analysis techniques using qualitative and quantitative approaches. The results of this study are the percentage of material experts 96.17% declared "Very Feasible" and the percentage of media expert validation 89.43% declared "Very Feasible". Practicality with a percentage of 98% is declared "Very Practical". The effectiveness of the N-Gain score obtained was 0.76 or g>0.7 and the N-Gain Percent Value of 76.01% was declared "Effective". It can be concluded that the Big Book learning media developed by researchers is very feasible, very practical, very effective to use on Theme 6 My Ideals Sub Theme 2 Great My Ideals Learning 2 Class IV SDN 067690 Medan Johor T.A 2022/2023. Keywords: Development, Big Book, 4D