Salinity is a major environmental restraint in arid and semi-arid regions. Excessive amounts of salt in natural soils and in saline irrigation reduce seed germination and plant growth of most plants in the agricultural lands of these regions. The purpose of this research was to investigate the effect of salinity on seed germination, growth performance, and physiological processes; such as chlorophyll content, chlorophyll fluorescence (Fv/Fm), and gas exchange of two Moringa species, Moringa oleifera and Moringa peregrina. Salinity treatments comprised 5 NaCl concentrations; (0, 50, 100, 150 and 200 mM). The germination test took place in petri dishes, while plants were grown in pots under controlled environments inside plant growth chambers. Results showed that seed germination was significantly affected by salinity. The effect of salinity on germination performance differed between the two species. For example, none of the two Moringa seeds germinated at the high level of salinity (200 mM), while M. oleifera seeds germinated at 150 mM and those of M. peregrina showed no signs of germination. Results demonstrated that salinity significantly reduced all growth parameters of the two Moringa species. However, low salinity (50 mM) enhanced all growth parameters and the photosynthetic performance of the two Moringa species compared to the control plants. The chlorophyll content was not affected by salinity for both species, but the saturation rate of photosynthesis was inhibited, and in particular under high NaCl concentration. The effect of salinity on quantum yield followed the same effect pattern as for the saturation rate of photosynthesis, while the (Fv/Fm) was not significantly affected. The two species of Moringa, M. oleifera and M. peregrina differed in the mechanisms of salt tolerance; for example, M. oleifera expressed high salt tolerance at germination phase, whereas M. peregrina demonstrated high photosynthesis rates at low and medium levels of salinity. The physiological responses of M. peregrina to withstand medium levels of salinity makes it a more successful species in harsh environments such as that of Saudi Arabia.