Sekolah minggu memiliki peranan penting dalam membangun dasar iman anak-anak sejak dini. Oleh karena itu, perancangan interior ruang sekolah minggu harus dibuat senyaman mungkin agar anak-anak dapat menikmati pengalaman beribadah dan bertumbuh dalam iman mereka. Ruang ibadah anak di GKI Kosambi Baru sebelumnya belum memadai karena terletak di lantai 3 sebagai ruang darurat yang belum mempertimbangkan aspek kenyamanan dan keselamatan anak. Penelitian ini bertujuan untuk merancang ruang sekolah minggu yang tidak hanya menarik minat anak-anak melalui aspek visual, namun juga menghadirkan kenyamanan ruang melalui penggunaan furnitur ergonomis, fasilitas yang memadai, serta menciptakan kondisi akustik yang mendukung. Metode perancangan menggunakan pendekatan Maureen Mitton, dengan fokus utama pada analisis dan implementasi material akustik untuk mencapai standar kenyamanan suara di ruang kelas. Hasil penelitian menunjukkan bahwa perancangan ini berhasil menciptakan ruang ibadah anak yang nyaman, aman, dan mendukung aktivitas rohani anak-anak. Pengujian akustik yang dilakukan membuktikan bahwa penggunaan material akustik mampu menurunkan tingkat kebisingan ke dalam standar kenyamanan akustik ruang kelas anak, sehingga suasana ibadah menjadi lebih kondusif. Secara keseluruhan, perancangan ini telah mempertimbangkan aspek warna, bentuk, ergonomi furnitur, keamanan, pencahayaan, penghawaan, serta akustik ruang, yang secara harmonis mendukung terciptanya pengalaman beribadah yang menyenangkan dan bermakna bagi anak-anak / Sunday school plays a vital role in building the foundation of children's faith from an early age. Therefore, the interior design of Sunday school spaces must be made as comfortable as possible so that children can enjoy their worship experience and grow in their faith. The children's worship space at GKI Kosambi Baru was previously inadequate, as it was located in an attic area used as an emergency space that did not consider the aspects of children's comfort and safety. This study aims to design a Sunday school environment that not only attracts children's interest through visual elements but also provides spatial comfort through the use of ergonomic furniture, adequate facilities, and the creation of supportive acoustic conditions. The design method employs Mauren Mitton’s approach, with a primary focus on the analysis and implementation of acoustic materials to achieve the standard for classroom acoustic comfort. The results show that the design successfully creates a worship space that is comfortable, safe, and supportive of children's spiritual activities. Acoustic testing demonstrates that the use of acoustic materials effectively reduces noise levels to meet the standards of children's classroom acoustic comfort, making the worship atmosphere more conducive. Overall, the design carefully considers aspects of color, form, furniture ergonomics, safety, lighting, ventilation, and acoustics, harmoniously supporting a pleasant and meaningful worship experience for children.