Large amounts of litter have accumulated across all parts of our oceans in less than fifty years. Litter has thus become a serious threat to the marine environment, aquatic life and humankind, whose welfare is closely linked with ocean health. Research on marine litter is currently taking a great leap forward and has substantially increased our knowledge of the amount and composition of litter as well as its impacts on the marine environment, aquatic life and people. However, the sheer number of studies scattered all around the globe has rendered this topic increasingly intangible making it difficult for policy makers, public authorities, media and the general public to unearth important information needed to address the urgent questions. LITTERBASE summarises results from 1,549 scientific studies in understandable global maps and figures and opens scientific knowledge on marine litter to the public.