<![CDATA[ABSTRACT This study aims to determine the effect of the Team Based Learning (TBL) model on the mathematics learning outcomes of fifth-grade students on the topic of data collection and presentation at UPT SDN 060879 Medan Timur in the 2025/2026 academic year. The research was motivated by students' low active participation, limited peer interaction, and suboptimal mathematics learning outcomes under teacher-centered instruction. A quantitative approach with a One Group Pretest-Posttest experimental design was employed, involving 30 fifth-grade students selected through purposive sampling. Data were collected through learning achievement tests and analyzed using the Liliefors normality test, product moment correlation, coefficient of determination, and t-test. The results showed that students’ average learning outcomes increased from 45.46 in the pretest to 85.73 in the posttest. Learning mastery also increased from 10% to 93%. The t-test results showed that the t-value (33.224) was higher than the t-table value (2.048), with a significance level of 0.000. Therefore, Team Based Learning had a significant effect on students’ mathematics learning outcomes. It is concluded that the Team Based Learning model has a significant effect on improving fifth-grade students' mathematics learning outcomes, and is recommended as an alternative instructional approach that fosters active engagement and student collaboration. ABSTRAK Penelitian ini bertujuan untuk mengetahui pengaruh model pembelajaran Team Based Learning (TBL) terhadap hasil belajar matematika siswa kelas V pada materi pengumpulan dan penyajian data di UPT SDN 060879 Medan Timur Tahun Ajaran 2025/2026. Permasalahan yang melatarbelakangi penelitian ini adalah rendahnya partisipasi aktif siswa, minimnya interaksi antarsiswa, serta hasil belajar matematika yang belum optimal akibat pembelajaran yang masih berpusat pada guru. Penelitian menggunakan pendekatan kuantitatif dengan metode eksperimen desain One Group Pretest-Posttest, melibatkan 30 siswa kelas V yang dipilih melalui teknik purposive sampling. Data dikumpulkan melalui tes hasil belajar dan dianalisis menggunakan uji normalitas Liliefors, uji koefisien korelasi product moment, uji koefisien determinasi, dan uji hipotesis (uji-t). Hasil penelitian menunjukkan bahwa rata-rata hasil belajar siswa meningkat dari 45,46 pada pretest menjadi 85,73 pada posttest. Ketuntasan belajar juga meningkat dari 10% menjadi 93%. Hasil uji-t menunjukkan bahwa nilai thitung 33,224 > ttabel 2,048 dengan signifikansi 0,000, sehingga terdapat pengaruh yang signifikan model Team Based Learning terhadap hasil belajar matematika siswa. Disimpulkan bahwa model Team Based Learning berpengaruh signifikan terhadap peningkatan hasil belajar matematika siswa kelas V, sehingga direkomendasikan sebagai alternatif pembelajaran yang mendorong keterlibatan aktif dan kerja sama siswa.]]>
