Sulfur (S) is one of the essential nutrients for plant growth, playing an important role in litter decomposition process. However, till now, we know little about litter initial S concentration (i.e., S concentration in freshly fallen litter) at the global scale. Here, based on 310 observations collected from 83 publications, we quantitatively assessed the global patterns of litter initial S concentration. We also evaluated the effects of mycorrhizal association [arbuscular mycorrhiza (AM), ectomycorrhiza (ECM), and both AM and ECM], taxon group (gymnosperm and angiosperm), life form (tree, shrub, and herb), leaf type (broadleaf and conifer), soil properties, and climate on litter S concentration. Results showed that (1) the global average S concentrations varied significantly among different litter types, which were 2.22, 0.801, 0.691, 1.57, 1.31, 0.468, and 0.110 g/kg in leaf, branch, root, stem, fruit, bark, and wood tissues, respectively; (2) the initial S concentration of leaf litter from shrubs was lower than that from herbs and trees, while root litter S concentration from ECM plants was lower than AM plants and plants associated with both AM and ECM fungi; (3) the initial S concentration of leaf, branch, and root litter of angiosperms was higher than that of gymnosperms, while S concentration of leaf, branch, and root litter of broadleaf trees was significantly higher than that of coniferous trees; (4) precipitation in the wettest month, the maximum temperature in the warmest month, and mean annual temperature were the main driving factors of S concentration in branch litter, while the minimum temperature of the coldest month, mean annual temperature, and total soil nitrogen concentration were the main driving factors of root litter S concentration. Results found in this study will help to better understand the role of S in litter decomposition as well as the associated material cycling processes.