Salinity stress is perhaps the most significant abiotic factor negatively impacting agricultural production globally, especially in semi-arid and arid ecosystems. The expanding area of saline soils, fuelled both by natural forces and human activities including poor irrigation practices and climate change, represents a serious threat to global food security. This chapter provides a comprehensive overview on the distribution, possible causes, mechanisms, impacts, modelling, assessment and mitigation strategies related to salinity stress in crops and cropping systems. Salinity affects water absorption, causes ionic and osmotic stress, and results in nutrient imbalances and oxidative damage to plants as well as deteriorate the soil health and carbon storage. Such physiological and biochemical alterations cause decreased germination, dwarfism, chlorosis, and finally considerable yield loss. The chapter also elucidates crop-specific reactions to salinity stress, including diversity in tolerance among species and cultivars. Several predictive models under salinity stress (e.g. Maas–Hoffman, Genuchten–Hoffman etc.) also have been discussed here. The mechanisms of salinity tolerance, including ion homeostasis, osmotic adjustment, antioxidant defence, and hormonal regulation, are explained in detail. Furthermore, the contribution of molecular and biotechnological strategies in modulating salinity tolerance, such as the application of salt-tolerant genes, marker-assisted selection, and CRISPR-Cas technology, is critically analysed. The possibility of sustainable management practices, including the adoption of salt-tolerant varieties, soil fertilization, and optimal irrigation practices, is also stressed. This chapter aims to shed light on the innovative approaches such as nanopriming, biosaline agriculture, floating farms etc. as emerging solutions, and to explore those strategies which may aid in the development of resilient cropping systems under saline environments.