In order to investigate the effect of zeolite on growth indices, yield and grain yield components and protein of lentil in dryland and supplementary irrigation conditions, a field study was conducted in Shahrekord University, Shahrekord, Iran. The experiment was performed as a split plot in a randomized complete block design with three replications. The main factor included three levels of irrigation (rainfed, one stage of supplementary irrigation and two stages of supplementary irrigation) and the second factor included the application of three levels of zeolite (0, 10 and 20 tons ha-1). The results showed that supplementary irrigation increased the grain yield. Application of zeolite moderated the effect of drought stress. Zeolite improved grain yield, this improvement occurred under both supplementary irrigation and rainfed conditions. Though, the interaction of supplementary irrigation and zeolite on yield and yield components was not statistically significant. Supplementary irrigation and zeolite had a significant effect on growth indices and improved growth indices during the growing season. The highest grain yield (1741 kg ha-1) was obtained when supplementary irrigation was applied at two stages. Application of 20 tons ha-1 of zeolite increased grain yield by 50% compared to the control. Therefore, according to the findings of the present study, in conditions of water restriction, application of 20 tons ha-1 of zeolite may benefit lentil cultivation in Shahrekord, Iran.