Respiratory viral infections such as SARS-CoV-2, respiratory syncytial virus (RSV) and influenza A virus (IAV) are still global public health challenges due to their ability to cause annual epidemics and instigate global pandemics. We explored the use of RNA interference (siRNA) technology as a therapeutic approach to target and repress pandemic potential respiratory viruses, including IAV, RSV, and SARS-CoV-2. SiRNAs were designed to bind ultra-conserved viral genome regions of the respective viruses to prevent viral escape through mutations. siRNAs targeting essential viral genes were transfected into cell lines infected with each virus, with Lipofectamine 3000. The study evaluated single, double, and triple combinations of siRNAs for their antiviral effects using an immunoplaque assay (iPA). Results showed that single siRNA treatments reduced viral replication, while double and triple siRNA combinations significantly enhanced antiviral activity across all tested viruses. In triple siRNA treatments, the reduction in viral plaque formation was substantial across RSV, IAV, and SARS-CoV-2, indicating a broad-spectrum antiviral response. This multiplexing strategy demonstrates the potential for developing siRNA-based therapies against diverse respiratory viruses by targeting multiple viral genes or conserved host interactions. The findings suggest that siRNA cocktails may provide a robust, adaptable tool in antiviral therapy, though challenges remain in refining target specificity, ensuring effective delivery, and accommodating viral diversity to optimise this approach for clinical use.