WHO| The World Health Organization’s (WHO) 2020 annual review of the clinical and preclinical antibacterial pipelines evaluates the potential of antibacterial candidates in different stages of development. The review addresses drug-resistant bacteria outlined in the WHO Bacterial Priority Pathogens List, Mycobacterium tuberculosis and Clostridioides difficile. The clinical pipeline part of the report assesses antibacterial drug candidates in clinical development stages worldwide, including direct-acting small molecules, biological agents, and for the first time non-traditional antibacterial medicines in the pipeline. In addition, the 2020 clinical pipeline review includes an extended account on traditional candidates in Phase 3 of clinical development, highlighting their potential clinical utility. The second part of the report focuses on candidates in preclinical development worldwide. It covers direct-acting small molecules, biological agents, vaccines, and non-traditional medicines in preclinical development. This report is part of the WHO’s efforts to prioritize and coordinate global research and development (R&D) efforts to address the discovery void in antibacterial drug development.