This study aims to describe in depth how the implementation of the Team Games Tournament (TGT) cooperative learning model can contribute to improving students' mathematics learning outcomes. To achieve this goal, this study was designed as a Classroom Action Research (CAR) that follows a systematic and cyclical flow. The research process begins with a careful planning stage (plan), where learning strategies and instruments are prepared. Furthermore, the action implementation stage (act) is carried out by applying the TGT model in the teaching and learning process in the classroom. During the implementation of the action, comprehensive observations are made of student and teacher activities, as well as class dynamics. Data were collected through various methods, including tests to measure learning outcomes, interviews to obtain student and teacher perspectives, documentation in the form of photos or videos of activities, and field notes to record important events. After the data was collected, data analysis was carried out through three main stages: data reduction to sort out relevant information, presenting data in an easily understood form, and drawing conclusions. The last stage is reflection, where researchers analyze the findings to identify successes, obstacles, and areas of improvement that form the basis for planning the next cycle. The results of the study showed the effectiveness of the TGT model, as evidenced by a significant increase in student learning outcomes through two cycles of action. In the first cycle, the average student score reached 60 with a success rate of 18.52%. A substantial increase occurred in the second cycle, where the average student score jumped to 80.74 with a success rate of 85.18%, indicating that the TGT learning model was successfully implemented and had a positive impact. ABSTRAKPenelitian ini bertujuan untuk mendeskripsikan secara mendalam bagaimana implementasi model pembelajaran kooperatif tipe Team Games Tournament (TGT) dapat berkontribusi pada peningkatan hasil belajar matematika siswa. Untuk mencapai tujuan tersebut, penelitian ini dirancang sebagai Penelitian Tindakan Kelas (PTK) yang mengikuti alur sistematis dan siklikal. Proses penelitian dimulai dengan tahap perencanaan (plan) yang cermat, di mana strategi dan instrumen pembelajaran disiapkan. Selanjutnya, tahap pelaksanaan tindakan (act) dilakukan dengan menerapkan model TGT dalam proses belajar mengajar di kelas. Selama pelaksanaan tindakan, dilakukan pengamatan (observe) secara komprehensif terhadap aktivitas siswa dan guru, serta dinamika kelas. Data dikumpulkan melalui berbagai metode, termasuk tes untuk mengukur hasil belajar, wawancara untuk mendapatkan perspektif siswa dan guru, dokumentasi berupa foto atau video kegiatan, serta catatan lapangan untuk merekam kejadian-kejadian penting. Setelah data terkumpul, dilakukan analisis data melalui tiga tahap utama: reduksi data untuk memilah informasi relevan, penyajian data dalam bentuk yang mudah dipahami, dan penarikan kesimpulan. Tahap terakhir adalah refleksi (reflection), di mana peneliti menganalisis temuan untuk mengidentifikasi keberhasilan, kendala, dan area perbaikan yang menjadi dasar untuk perencanaan siklus berikutnya. Hasil penelitian menunjukkan efektivitas model TGT, yang dibuktikan dengan peningkatan signifikan hasil belajar siswa melalui dua siklus tindakan. Pada siklus pertama, rata-rata nilai siswa mencapai 60 dengan persentase keberhasilan sebesar 18,52%. Peningkatan yang substansial terjadi pada siklus kedua, di mana rata-rata nilai siswa melonjak menjadi 80,74 dengan persentase keberhasilan mencapai 85,18%, mengindikasikan bahwa model pembelajaran TGT berhasil diimplementasikan dan memberikan dampak positif.