This study was conducted to investigate if quercetin (QRN) may ameliorate apoptosis and oxidative stress in post-thaw dog sperm. Herein, we evaluated the post-thaw apoptosis and oxidative stress after treatment with QRN (control, 25, 50, and 100 µM) in freezing of dog semen. The oxidative stress index was significantly affected (p<0.05) between the various concentrations of QRN and the control (17.56 ± 1.02, 7.54 ± 0.48, 5.66 ±0.80, and 10.41 ± 0.69), respectively. The apoptosis index was 9.1 ± 1.34, 6.66 ± 0.58, 6.77 ± 0.66, and 5.38 ± 0.86 in the control, and 25, 50, and 100 µM QRN treatment groups, respectively (p< 0.05). The effects of ameliorated cryo-induced damage by QRN on post-thaw sperm quality were also observed through improved structural and functional tests. Sperm treated with 50 µM QRN showed significantly higher motility (51.8 ± 2.1% vs. 43.1 ± 1.4%, P < 0.05), survival rates (46.9 ± 0.7% vs. 43.9 ± 0.4%, P < 0.05), and mucus penetration than control group, respectively. Results demonstrate that supplementing freezing buffer with 50 µM QRN reduced oxidative damage and improved the quality of post-thaw dog sperm.