Intermittent rivers and ephemeral streams (IRES) can support a diverse and often abundant terrestrial and semiaquatic invertebrate (TSAI) fauna. This fauna can inhabit the shoreline, the surface of exposed gravel bars, unsaturated gravels, dry riverbeds, riparian zones, and floodplains. TSAI communities are typically dominated by ground-dwelling beetles, ants, and spiders, but many other taxonomic groups are represented. Much less is known about the species composition and ecological roles of TSAIs of IRES than their aquatic counterparts. In this chapter, we discuss the habitat requirements of TSAI fauna, as well as their taxonomic and functional diversity. We describe approaches to sampling them and the collection equipment required, the adaptations of IRES invertebrates to flow intermittence, and their roles in processing organic matter and nutrients. Finally, we identify threats to TSAI communities, outline existing knowledge gaps, and suggest how to manage IRES ecosystems to conserve or restore TSAI biodiversity. The explicit inclusion of IRES in management and legislation will help safeguard the diversity of TSAIs.