Recent insight into the pathophysiology of severe coronavirus disease 2019 (COVID-19) has implicated hyperactivation of the immune response, resulting in a “cytokine storm,” which can lead to excessive immune-cell infiltration of the lungs, alveolar damage, decreased lung function, and death. Several cytokines implicated in the COVID-19–associated cytokine storm predominantly signal through the Janus kinase (JAK)/signal transducer and activator of transcription pathway. Ruxolitinib is a selective inhibitor of JAK1 and JAK2 that has been explored in small studies of patients with COVID-19–associated cytokine storm. Early clinical data from these trials, combined with a body of preclinical and clinical evidence in other inflammatory conditions, support exploration of the efficacy and safety of ruxolitinib in these patients in larger, well-controlled trials. Here we describe the designs of three such ongoing clinical trials. RUXCOVID is a phase 3 randomized, double-blind, multicenter study of ruxolitinib 5 mg twice daily (BID) vs placebo (both plus standard of care) in patients with COVID-19–associated cytokine storm. 369-DEVENT is a phase 3, randomized, double-blind, placebo-controlled, multicenter study of ruxolitinib 5 or 15 mg BID vs placebo (all plus standard of care) in patients with COVID-19–associated acute respiratory distress syndrome who require mechanical ventilation. Patients with severe COVID-19–associated cytokine storm who are ineligible for these trials can receive ruxolitinib through an Expanded Access Program (EAP) in the United States and similar programs outside of the United States. RUXCOVID and 369-DEVENT will provide insight into the efficacy and safety of ruxolitinib in hospitalized patients prior to or during ventilator use. If these trials are successful, ruxolitinib could improve outcomes for patients with COVID-19 as well as lessen the overall burden on the health care system.