In the present study, potential evapotranspiration (PET) is estimated using geographic information system (GIS) and remote sensing (RS) data. Linear imaging self-scanning sensor (LISS-III) satellite images of Tapi river basin area were used in the present study. The study area is classified into five different zones, namely forest land, agricultural land, barren land, urban land and water bodies by supervised classification. NDVI values for the respective zones (class) were used to estimate crop coefficient (Kc) using linear regression model. Reference evapotranspiration (ETo) was calculated from Penman–Monteith model and PET was calculated by multiplying the Kc and ETo. The results obtained by this methodology were validated using actual evapotranspiration. A new linear model was developed for the study area between NDVI and Kc. Developed methodology for the determination of Kc derived from RS data and NDVI-Kc model may be useful for irrigation scheduling and estimating water use efficiency