Salinity stress is one of the most severe abiotic constraints affecting aquatic and semi-aquatic plant productivity, particularly in ecologically and economically significant species such as Azolla spp. and Lemna minor. These plants are widely recognized for their rapid growth, high protein content, and application in sustainable agriculture, animal feed, and phytoremediation systems. The present study investigates the comparative role of salicylic acid (SA) in modulating soluble protein accumulation in Azolla spp. and Lemna minor under salinity-induced stress conditions. Salicylic acid, a key phytohormone, is known to regulate stress signaling pathways, enhance antioxidant defense mechanisms, and stabilize protein metabolism under adverse environmental conditions. The study synthesizes biochemical and physiological responses based on salinity-induced osmotic imbalance, reactive oxygen species (ROS) accumulation, and phytohormonal crosstalk. Findings indicate that SA application significantly enhances soluble protein content by improving osmolyte balance, stabilizing cellular structures, and regulating stress-responsive gene expression. Comparative analysis reveals species-specific differences in protein accumulation efficiency, with Azolla spp. showing higher metabolic resilience under moderate salinity, while Lemna minor exhibits stronger adaptive regulation under prolonged exposure. The study emphasizes the integrative role of SA in enhancing salt stress tolerance through osmolyte-mediated signaling networks and phytohormonal interaction pathways. This work contributes to understanding stress physiology in aquatic plants and provides a foundation for optimizing their use in saline agriculture systems.