Bovine parainfluenza virus type 3 (BPIV3) is a widespread respiratory pathogen of cattle with a significant impact on herd health and productivity. As a primary viral agent within the bovine respiratory disease complex (BRDC), it predisposes animals to secondary bacterial infections. It contributes to substantial economic losses through morbidity, mortality, and reduced performance. The virus circulates globally in three major genotypes (A, B, and C), with considerable genetic variation that complicates vaccine effectiveness and underscores the importance of genomic surveillance. Transmission occurs mainly via respiratory droplets, with young calves under stress being most susceptible. Pathogenesis involves disruption of mucociliary clearance and damage to respiratory epithelium, leading to bronchitis, bronchiolitis, and pneumonia. Clinical signs range from mild fever and nasal discharge to severe respiratory distress, while immunity depends on both humoral and cellular responses, influenced by maternal antibodies. Diagnosis relies on virus isolation, molecular assays, serology, and immunohistochemistry, and prevention focuses on husbandry practices and vaccination, though protective outcomes remain variable. Understanding BPIV3’s biology, epidemiology, and immune interactions is essential for effective control and improved cattle health worldwide.