Neogene is one of the important periods in the earth's history in view of significant changes that took place during the period in climatic and oceanographic conditions. Radiolarians from well preserved cores, uplifted marine sequences, and surface sediments from the northern Indian Ocean provided opportunity to reconstruct the Neogene oceanographic and climatic events. Studies based on radiolarians from land-based sections revealed episodes of cooling and warming in the late Early Miocene to Middle Miocene. Investigations of radiolarian upwelling fauna in the cores from the western Arabian sea demonstrated strengthening and weakening of upwelling during late Middle Miocene to Recent. Examination of radiolarians from surface sediments suggested presence of Antarctic Bottom water in the Mozambique and Madagascar basins of the western Indian Ocean. Certain radiolarian species are found useful in understanding paleomonsoonal changes and have been used to interpret such changes.