Medicinal plants represent a promising source of antiviral agents against respiratory viruses, supported by evidence from in vitro, in vivo, and in silico studies. Key bioactive compounds, including silymarin from Silybum marianum, germacrone from Geranium macrorrhizum, and licochalcone A from Glycyrrhiza glabra, have demonstrated the ability to reduce viral replication, inhibit viral enzymes such as neuraminidase, interfere with viral entry, and modulate host immune signaling pathways, enhancing viral clearance. Traditional multi-herb formulations, including Japanese medicines like Shahakusan and Hochuekkito, also show measurable antiviral activity, reflecting historical therapeutic applications. Despite these promising findings, challenges remain in standardizing extracts, evaluating pharmacokinetics and safety, and bridging in vitro potency to in vivo efficacy. Integrating in silico prioritization with systematic preclinical studies is essential to guide the selection of candidate phytochemicals for clinical translation. Overall, these findings highlight the potential of plant-derived antivirals as safe, effective, and complementary therapeutics for both human and veterinary respiratory viral infections.