Watermelon mosaic virus (WMV) is a potent potyvirus of the bean common mosaic virus lineage that has a global economic impact on cucurbit plants. This leads to substantial economic losses owing to its detrimental effects on fruit quality and production, particularly in watermelons and other cucurbit plants. WMV inflicts severe harm, potentially causing nearly 100% yield reduction during early- and mid-season infections and approximately 70% loss in late-season infections. Researchers have identified two viruses, WMV1 and WMV2, using cross-protection experiments, serological analyses, and host-range observations. WMV1 demonstrates a close relationship with papaya ringspot virus (PRSV), prompting its reclassification as the “W” strain of PRSV. Similarly, WMV2 has been officially identified as a Watermelon mosaic virus. A distinct serological variant from Morocco, known as Moroccan watermelon mosaic virus (MWMV), was identified, with potential extensions to the South African watermelon mosaic isolate. This reclassification has led to the evolution of the original Watermelon mosaic virus complex into three distinct virus species: WMV, PRSV, and MWMV. This chapter provides a comprehensive overview of the Watermelon mosaic virus (WMV), presenting essential insights for researchers aiming to deepen their understanding of the virus and formulate effective management strategies. It encompasses diverse aspects, including viral distribution, symptoms, genome organization, epidemiology, transmission, and management. This understanding lays the groundwork for devising approaches to control and mitigate the impacts of WMV on crops.