The present study was carried out to investigate the cytological, histopathological, and immunohistochemical profiles of eleven cases of canine mammary gland tumors. Based on cytological characteristics, two cases of benign tumors and nine cases of malignant mammary gland tumors were tentatively diagnosed whereas one case of benign tumor and ten cases of malignant tumors were later on confirmed by histopathology. Considering histopathology as a gold standard diagnostic technique for tumors, one false positive and two false-negative results were obtained. For the determination of origin and nature of the tumor, immunohistochemistry was performed on all cases using PCNA, Ki-67, pan-cytokeratin, vimentin, and desmin biomarkers. All cases showed immunoreactivity with PCNA, Ki-67, and pan-cytokeratin whereas no immunoreactivity was found with the desmin. However, carcinoma mixed type and malignant myoepithelioma showed immunoreactivity with vimentin; the rest of the tumors did not show any immunoreactivity with the same.