The study evaluated the physiological and phytochemical responses of red amaranth (Amaranthus tricolor L.) to foliar-applied salicylic acid (SA; 0.005 mM) and calcium (CaSO4·2H2O; Ca, 2.5 mM) either alone or in combination (SA + Ca) under conditions of 100 mM NaCl salinity. The combined application of salicylic acid and calcium can be a better strategy for improving the salinity tolerance of amaranth under salt-stressed conditions.