Respiratory diseases caused by viral pathogens represent a significant global health burden. After facing a severe pandemic like COVID-19, respiratory diseases arise as a major area of public health and research. The persistent and ubiquitous threat that viral infections pose to global health highlights the urgent need for resourceful approaches to mitigate the effects of viruses. Viral infections continue to be a major cause of morbidity and mortality even though conventional antiviral drugs like interferon and ribavirin exhibit some level of effectiveness against some viruses in testing environments. As resistance to conventional antiviral drugs increases and concerns about side effects remain, medicinal plants have gained importance as alternative therapeutics due to their antiviral and immunomodulatory properties. This chapter explores the dual role of medicinal plants in combating respiratory viruses and modulating immune responses. We address the molecular mechanisms underlying the antiviral effects of important phytochemicals such as flavonoids, alkaloids, and terpenoids, which inhibit virus replication, attachment, and entry into host cells. In addition, we discuss how these compounds regulate immune functions, reduce inflammation and cytokine storms and thus prevent the exacerbation of respiratory infections. Highlighting current preclinical and clinical evidence, we highlight the potential of medicinal plants to complement existing antiviral therapies and advocate for their inclusion in integrative approaches to the treatment of respiratory diseases.