ABSTRAK Keaktifan siswa dalam pembelajaran menjadi salah satu tantangan yang perlu diatasi guna meningkatkan kualitas pendidikan. Penelitian ini bertujuan untuk menganalisis efektivitas model pembelajaran kooperatif tipe Student Teams Achievement Division (STAD) dalam meningkatkan keaktifan siswa pada pembelajaran sistem pernapasan di kelas V SDN 03 Cipaisan, Kabupaten Purwakarta. Metode penelitian menggunakan pendekatan kualitatif deskriptif dengan pengumpulan data melalui observasi, wawancara, dan dokumentasi. Indikator keaktifan siswa meliputi partisipasi, keberanian bertanya, dan kerja sama. Hasil penelitian menunjukkan bahwa penerapan STAD meningkatkan partisipasi siswa secara signifikan, dengan 84% siswa menunjukkan antusiasme tinggi. Namun, indikator bertanya masih menjadi tantangan, dengan 68% siswa tergolong pasif. Faktor keberhasilan meliputi pendekatan kolaboratif, motivasi ekstrinsik, dan stimulus awal positif. Model STAD terbukti efektif menciptakan suasana pembelajaran interaktif dan meningkatkan kualitas pembelajaran. Untuk optimalisasi, disarankan strategi tambahan seperti scaffolding untuk meningkatkan kepercayaan diri dan aktivitas siswa dalam bertanya. Kata kunci: STAD, Keaktifan Pembelajaran, Siswa. ABSTRACT Student activity in learning is one of the challenges that needs to be overcome to improve the quality of education. This research aims to analyze the effectiveness of the Student Teams Achievement Division (STAD) type cooperative learning model in increasing student activity in learning the respiratory system in class V at SDN 03 Cipaisan, Purwakarta Regency. The research method uses a descriptive qualitative approach with data collection through observation, interviews, and documentation. Indicators of student activity include participation, courage to ask questions, and cooperation. The results showed that the implementation of STAD increased student participation significantly, with 84% of students showing high enthusiasm. However, asking for indicators is still challenging, with 68% of students classified as passive. Success factors include a collaborative approach, extrinsic motivation, and positive initial stimulus. The STAD model has proven effective in creating an interactive learning atmosphere and improving the quality of learning. For optimization, additional strategies such as scaffolding are recommended to increase students' confidence and activity in asking questions. Keywords: STAD, Learning Activeness, Students.