Mangroves are among the most productive ecosystems on Earth, yet they are disappearing at a dramatic rate. Mangrove sediments harbor microscopic nematodes, which show specific responses to variations of sediment physicochemical conditions, thus being potential bioindicators for conservation purposes. Nematode communities are subject to the strong heterogeneity of mangroves and predicting their distribution remains laborious at global and regional scale, thus hampering final statements about bioindication. In this review, we analyze relevant research on mangrove nematode diversity in order to identify the ecological mechanisms shaping the nematode community at the global, local and micro scales, and to hierarchize the environmental drivers responsible for nematode genera sorting. At the global scale, nematode genera richness is positively influenced by latitude and community composition changes according to geographical regions. At the local scale, nematode richness, density and community composition follow opposite patterns along a land-sea continuum and mangrove trees may be responsible for the variations of sediment chemistry leading to such community patterns. At the microhabitat scale, the community shows unexpected similarities between a priori different habitats. Epistrate and detritus feeders dominate mangroves, but except for trophic groups, the use of functional traits is inconsistent among studies, thus impeding conclusions. Further understanding of the role of environmental filters in shaping nematode diversity at different spatial scales cannot overlook data gaps in unexplored mangrove areas and the heterogeneity of microhabitats. Future studies should investigate nematode diversity with cutting-edge approaches, such as β-diversity partitioning, functional traits and metacommunity analysis, and eventually integrate nematodes, microbes and macrofauna in a comprehensive framework.