Most horticultural crops are considered highly perishable, and postharvest life is shortened if preservation technologies are not applied to reduce ripening, senescence, and prevent pathogens attacks. Salicylic acid (SA) is a plant hormone that can act as a signaling molecule in the plant responses to environmental stress or pathogenic attacks. It is also responsible for the onset of systemic acquired resistance in plants, which increases plant resistance to pathogenic attacks and alleviates the adverse effects of abiotic stress. Moreover, SA also plays a key role in delaying ripening of fruits, by inhibition of ethylene biosynthesis, which helps to maintain postharvest quality and to extend shelf life of fruits and vegetables. Additionally, SA effectively enhances the effects of biocontrol, obtaining better results when combined with antagonist yeasts to control rot and decay. Several environmental factors can alter endogenous SA levels of SA in the plants and elicit several defense mechanisms in plants. As a consequence, recent studies have focused on the effects of the exogenous application of SA. Examples of SA pre- and/or postharvest application in horticultural crops are described in the present chapter. The effects of SA application on fruits and vegetables, along with the possible mechanisms involved in the plant responses, are presented.