Olive is one of the most important fruit crops in Iran and the world. The olives are considered as moderately tolerate to salinity stress. Salinity is a common abiotic stress that seriously affects crop production in some parts of the world, particularly in arid and semi-arid regions. The tolerance of the olive to salt is to a great extent dependent on the cultivar. So, this study was done to assess the salt tolerance of four olive cultivars under greenhouse condition. For this purpose, one year rooted cutting of four olive cultivars (Amigdal, Dakal, Shiraz and Zard) and NaCl at 0, 100, 150 and 200 mM were used. The experiment was carried out as a factorial (4 4) based on completely randomized design with four replications. The result showed that salt stress significantly reduced the vegetative growth parameters including fresh and dry weight of root and shoot, stem length and leaf area, photosynthetic parameters, chlorophyll content, chlorophyll fluorescence ratio (Fv/Fm) and relative water content (RWC). With increasing salinity levels, the injury rating value of olive plants was significantly increased. Increasing the concentration of NaCl caused to increasing leaf electrolyte leakage and proline content. The results also indicated that there were significant differences between the used cultivars in the experiment, while Zard and Shiraz cultivars showed the highest leaf proline content, RWC, relative leaf chlorophyll content (RLCC), Fv/Fm ratio and photosynthetic parameter as compared with the other olive cultivars. The application of NaCl caused to accumulating Na + and reduced K + in leaves and roots of the olive cultivars. The highest leaves potassium content was observed in Zard and Dakal cultivars. The results indicated that there were a positively correlated between injury rating value, leaf electrolyte leakage, leaves proline contents and Na + contents of leaves and roots but correlated negatively with RWC, Fv/Fm ratio, leaf net photosynthetic rate and K + contents of leaves and roots. In overall the result shown that Zard was the most tolerance and Amigdal was the most sensitive olive cultivars to salt stress. Key words : Olive cultivars, Salt stress, Growth and photosynthetic parameters.