The global pandemic of novel coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has created an urgent need for effective antivirals. Remdesivir (formerly GS-5734) is a nucleoside analogue pro-drug currently being evaluated in COVID-19 clinical trials. Its unique structural features allow high concentrations of the active triphosphate metabolite to be delivered intracellularly and it evades proofreading to successfully inhibit viral RNA synthesis. In pre-clinical models, remdesivir has demonstrated potent antiviral activity against diverse human and zoonotic β-coronaviruses, including SARS-CoV-2. In this article we critically review available data on remdesivir with an emphasis on biochemistry, pharmacology, pharmacokinetics and in vitro activity against coronaviruses as well as clinical experience and current progress in COVID-19 clinical trials.