Penelitian ini bertujuan untuk mengetahui tingkat kelayakan media pembelajaran buletin dalam bentuk buku saku pada materi Termokimia di kelas XI SMA Swasta Iskandar Muda terhadap tanggapan pendidik dan peserta didik. Jenis penelitian yang digunakan adalah penelitian pengembangan (R&D) tipe Borg and Gall dengan pendekatan kualitatif. Jenis Borg and Gall yang dilakukan pada penelitian ini adalah 6 tahap, yaitu (1) potensi dan masalah, (2) pengumpulan data, (3) desain produk, (4) validasi desain, (5) revisi desain, dan (6) uji coba produk. Pengumpulan data dilakukan di SMA Swasta Iskandar Muda dengan sampel yang diambil 2 orang pendidik kimia dan 31 orang peserta didik yang dipilih secara purposive sampling. Kelayakan media buletin dalam bentuk buku saku dinilai oleh 4 orang validator yaitu 2 validator materi diperoleh persentase rata-rata 75,8% dan 2 validator media (desain) diperoleh presentase rata-rata sebesar 84,0%. Persentase tanggapan pendidik diperoleh rata-rata 70,47% dan peserta didik diperoleh 86,2%. Berdasarkan hasil penelitian yang didapat bahwa media buletin dalam bentuk buku saku yang telah dikembangkan layak digunakan dalam proses pembelajaran materi Termokimia. Peneliti menyarankan kedepannya dapat menggunakan buletin dalam bentuk buku saku bervariasi pada materi kimia lainnya. Kata Kunci: Buku Saku, Buletin, Media, Termokimia.   The research that has purpose to determine the feasibility of learning media in the form of a pocket booklet on thermochemical material in class XI Iskandar Muda Private High School on the responses of educators and students. This type of research is a Borg and Gall type research and development (R&D) with a qualitative approach. The Borg and Gall types conducted in this study are 6 stages, namely (1) potential and problems, (2) data collection, (3) product design, (4) design validation, (5) design revision, and (6) trial product. Data collection was carried out at Iskandar Muda Private High School with a sample taken by 2 chemical educators and 31 students. The feasibility of the bulletin media in the form of a pocket book was assessed by 4 validators namely 2 material validators obtained an average percentage of 75.8% and 2 media validators (designs) obtained an average percentage of 84.0%. Percentage of educator responses obtained an average percentage of 70.47% and students gained 86,2%. Based on the research results obtained that the bulletin media in the form of pocket books that have been developed are suitable for use in the learning process of Thermochemical material. Researchers suggest that in the future you can use bulletins in the form of varied pocket books on other chemical materials.   Keywords: Bulletin, Media, Pocket Book, Thermochemistry.