Thirteen-year satellite-derived data are used to investigate the temporal variability of net primary productivity (NPP) in the Oman upwelling zone and its potential forcing mechanisms. The NPP in the Oman upwelling zone is characterized by abnormal decrease during El Niño events. Such NPP decrease may be related to El Niño-driven anomalous summertime weak wind. During the summer following El Niño, the anomalous northeasterly wind forced by southwest Indian Ocean warming weakened the southwest monsoon and caused the Arabian Sea to warm. The abnormal wind weakened the coastal Ekman transport, offshore Ekman pumping and horizontal advection, resulting in reduced upward nutrient supply to the euphotic zone. A slightly declined trend in NPP after 2000 associated with a gradual decrease in surface monsoon winds is discussed.