Abstract: Respiratory viral infections pose serious threats to human health, particularly highlighted by recent pandemics caused by influenza viruses and coronaviruses. Natural products, characterized by their structural diversity and unique biological activities, offer promising resources for antiviral drug development. This review systematically summarizes the biological features, infection mechanisms, and antiviral targets of five major respiratory viruses—namely influenza virus, coronavirus, respiratory syncytial virus, human rhinovirus, and human metapneumovirus. It highlights recent progress in the discovery of antiviral natural products, including their chemical structures, mechanisms of action, and in vitro/in vivo activities. Many of these compounds not only inhibit viral entry and replication but also modulate host immune responses, exhibiting broad-spectrum, low-toxicity, and high-efficiency potential. This work aims to provide theoretical references and lead compound resources for future antiviral drug discovery and mechanistic research.