Technical Abstract: Nonpoint source (NPS) pollutants are recognized as the single greatest threat to surface and subsurface sources of drinking water throughout the world. The vadose zone serves as the conduit through which NPS pollutants travel through surface soil to groundwater supplies. Because of increased dependency on groundwater supplies, the ability to model groundwater vulnerability to the leaching of NPS pollutants through the vadose zone has grown in significance. Furthermore, the buildup of NPS pollutants such as salinity and trace elements (e.g., boron, selenium, etc.) in agricultural soils has created a need for identifying soils susceptible to the degradative effects of NPS pollutants upon crop productivity. Geographic information systems (GIS) have emerged as a useful tool in environmental modeling, particularly for NPS pollutants. A review is presented concerning the modeling of NPS pollutants in the vadose zone with GIS. Emerging technologies such as GIS act as catalysts to provide innovative approaches to heretofore unsolvable problems. The proliferation of GIS-based NPS pollutant models holds promise, yet caution is needed to avoid misuse of a potentially valuable environmental assessment tool for decision makers.