Salt tolerance of plants is evaluated by several models and most of them consider only soil salinity as the limiting criteria. In this study, impacts of climate over salt tolerance of plants were also considered and plant yield, plant height, number of leaves, amount of dry matter, soil salinity and plant water consumption were evaluated by using 3-D models. Therefore, relationships were established to express the combined effects of soil salinity and evapotranspiration on the yield and some growth parameters (plant height, number of leaves, dry matter content) of lettuce. The highest yield was obtained in low soil salinity and high evapotranspiration, whereas the lowest yield was obtained in high soil salinity and low evapotranspiration cases. The relationships between evapotranspiration-soil salinity and yield-some growth parameters were generally linear with increasing or decreasing tendencies. A wide range effect of evapotranspiration and soil salinity on the yield and some growth parameters of lettuce might be helpful for salinity management. In addition, the effects of salinity on growth, development and yield of lettuce can be used to derive some relationships between evapotranspiration and soil salinity.