Seed germination is the most sensitive stage to abiotic stress, including salt stress (SS). SS affects plant growth and performance through ion toxicity, decreases seed germination percentage, and increases the germination time. Several priming treatments were used to enhance germination under SS. The objectives of this study are to 1) identify priming treatments to shorten the emergence period; 2) evaluate priming treatments against the SS; 3) induce synchronized seed germination. Salt-sensitive “Burpee bibb’ lettuce seeds were treated with 0.05% Potassium nitrate, 3 mM Gibberellic acid, and distilled water (HP). All the primed and non-primed seeds were subjected to 100 mM NaCl or 0 mM NaCl. The 7-day experiment arranged in a complete randomized block design with four replications was conducted in a growth chamber maintained with 16/8 h photoperiod (light/dark), 60% relative humidity, and day/night temperature of 22/18 °C. The result indicated that HP seeds were better synchronized under SS. Similarly, FM and DM of cotyledon, hypocotyl, and radicle were highest in HP lettuce regardless of SS. Electrolyte leakage was the lowest in the HP lettuce, while other priming methods under SS increased membrane permeability leading to osmotic stress and tissue damage. Overall, the HP can be a suitable priming method to synchronize germination and increase FM and DM by creating the least osmotic stress and ion toxicity in lettuce under SS.