Continental shelves, which occupy approximately 9% of the Earth’s ocean area, are crucial for global organic carbon production and marine biodiversity. Their proximity to land and nutrient-rich upwelling zones makes them highly productive fishing grounds. Human activities, including overfishing, habitat destruction, and pollution, pose significant threats to their health and biodiversity. The Brazilian continental shelf, stretching over 7500 km, is divided into distinct ecoregions with varying environmental conditions and biological assemblages. This chapter aims to provide a comprehensive overview of the benthic communities inhabiting the southeastern Brazilian continental shelf, focusing on both the Southeastern Brazil (or South Brazil Bight) and Rio Grande (or Southern Subtropical Shelf) ecoregions within the Warm Temperate Southwestern Atlantic Province. The inner shelf of the Southeastern Brazil ecoregion is notably divided by São Sebastião Island (SSI), creating distinct zones that influence the benthic biodiversity and habitat types in the surrounding water. Additionally, the seasonal upwelling, near Cabo Frio, plays a crucial role in shaping the benthic communities of the Southeastern Brazil ecoregion, particularly on the outer shelf. While sediment characteristics are important for the distribution of the benthic fauna across the shelf, the La Plata plume and freshwater outflow from Patos Lagoon significantly shape the benthic faunal distribution in the inner shelf of the Rio Grande ecoregion. The Subtropical Shelf Front provides a rich food source for benthic organisms, supporting high biomass and diversity in the Rio Grande ecoregion. The influx of the Patagonian current can introduce benthic fauna from southern regions, further enhancing the ecological complexity of this ecoregion. Significant knowledge gaps exist in Brazil’s continental shelf due to historical neglect. Expanding our understanding of the benthic communities in the region is crucial for preserving these ecosystems. The knowledge of the benthic biodiversity on Brazil’s shelf is essential for maintaining vital ecological services, supporting sustainable resource management, and ensuring the well-being of both marine populations and society.