<p>Salinity is a major abiotic constraint limiting pineapple (<i>Ananas comosus</i>) growth and productivity, and strategies that improve stress acclimation during early developmental stages may enhance plant performance under adverse conditions. This study evaluated whether in vitro salinity priming could modulate subsequent physiological and growth responses of pineapple seedlings exposed to severe <i>ex vitro</i> salt stress. Seedlings were subjected to salinity conditioning during the in vitro phase and subsequently acclimatized under greenhouse conditions, with or without exposure to 500&#xa0;mM NaCl. Growth, gas exchange, chlorophyll fluorescence, and photosynthetic pigment content were assessed. Severe salinity reduced net CO₂ assimilation, stomatal conductance, transpiration, and biomass accumulation in both primed and non-primed plants. However, primed seedlings showed partial physiological acclimation, including a less pronounced decline in apparent carboxylation efficiency and maintenance of pigment concentrations under salinity. Contrasting <i>Ci/Ca</i> responses suggested differences in the balance between stomatal and non-stomatal limitations depending on priming history. Despite these physiological adjustments, priming did not improve biomass accumulation and was associated with reduced plant size even under non-saline conditions. These findings indicate that in vitro salinity priming can alter subsequent physiological responses in pineapple, but under the severe salinity imposed here, these adjustments were insufficient to promote growth recovery, suggesting a decoupling between selected physiological traits and biomass performance.</p>