Salt stress tolerance is a very complex phenomenon which involves many gene products. Rice plants can respond to the stress as a whole organism and as individual cells. Salt stress induces ionic stress and osmotic stress, which increases Na+ ion toxicity, disturbs ion homeostasis and alters cellular metabolism. To grow normally, properly divide and cope under adversarial conditions, plants use osmotic and ionic signaling to maintain osmotic and ion homeostasis, which help plants to tolerate salt stress. Osmotic stress affects the growth of plants, mainly by ABA dependent and ABA independent pathways; to overcome the salt stress, plants activate their downstream genes. Ionic stress, on other hand, activates the IP3 pathway and calcium signaling, which in turn activates the calmodulin pathway and salt overly sensitive (SOS) pathway to maintain ion homeostasis. This chapter describes the mechanism of salt stress tolerance and pathways in crop plants.