Abstract. – Zooplankton temporal and spatial distributions and additional environmental features of a Brazilian coastal lagoon were studied during three years. Despite its proximity to the sea and the occurrence of marine intrusion during the period of study, the lagoon was characterized as a freshwater environment. The zooplankton community consisted of 95 taxa, including holoplanktonic and meroplanktonic forms. Location, macrophyte colonization and river input were found to be key factors determining the distinct features of the zooplankton community. A canonical correspondence analysis revealed that water salinity and conductivity, suspended matter content and water transparency were the main factors behind the temporal differences in the frequency of occurrence and the abundance of the constant and common taxa. Predation pressure by invertebrates and fish probably determines the zooplankton community structure, favouring small-sized cladocerans as well as rotifers with anti-predatory strategies, and may also help explain the spatial distribution of larger zooplankters.