Coronavirus disease 2019 (COVID-19), triggered by the betacoronavirus SARS-CoV-2, has become one of the worst pandemics of our time that has already caused more than 250,000 deaths (JHU data-05/06/2020, https://coronavirus.jhu.edu/). Effective therapeutic approaches are urgently needed to reduce the spread of the virus and its death toll. Here, we assess the possibility of using interferon-lambda (IFNlambda), a third type of interferon sharing low homology with type I IFNs and IL-10, for treating COVID-19 patients. We discuss the unique role of IFNlambda in fine-tuning antiviral immunity in the respiratory tract to achieve optimal protection and minimal host damage and review early evidence that SARS-CoV-2 may impair IFNlambda induction, leading to a delayed type I IFN-dominated response that triggers hyperinflammation and severe disease. We also consider the potential windows of opportunity for therapeutic intervention with IFNlambda and potential safety considerations. We conclude that IFNlambda constitutes a promising therapeutic agent for reducing viral presence and hyperinflammation in a single shot to prevent the devastating consequences of COVID-19 such as pneumonia and acute respiratory distress syndrome (ARDS).