Reefs are highly diverse environments that provide important ecosystem services such as fisheries, tourism and coastal protection. Reefs are distributed along most of the Brazilian continental shelf, being divided into five distinct ecoregions across nearly 3000 km of latitudinal range. Brazilian reefs are broadly comprised of four typologies found in a unique and heterogeneous geological context: true coral reefs, coralline algal reefs, sandstone reefs and rocky reefs. These reefs were formed largely under the influence of the warm Brazil Current and numerous large rivers, which function as geographical barriers and contribute to elevated sediment and nutrient conditions. Brazilian reef biodiversity is considerably lower than that of the Caribbean and Indo-Pacific but displays a high degree of endemism. The coral fauna is composed of 21 scleractinian and milleporid species, most of which are massive-shaped and stress-tolerant. Other reef-building organisms include bryozoans, vermetids and crustose coralline algae. The latter are responsible for building extensive rhodolith beds. However, Brazilian reefs currently face the impacts of multiple anthropogenic stressors. The main threat is global warming, which has caused intense coral bleaching. Additional stressors include ocean acidification, overfishing and pollution. Increasing the effectiveness and enforcement of existing marine protected areas, as well as creating new ones, is critical against local-scale stressors, while global stressors must be dealt with by curbing the emission of greenhouse gases.