Salinity is one of the abiotic stresses that most limit crop productivity. This makes it essential to search for alternatives that would ensure the viability of production under such conditions. The aim of this work was to evaluate the potential of silicon for reducing the detrimental effects of salt stress on seed germination and initial seedling growth in five lettuce cultivars. Two experiments were carried out in a completely randomised design with four replications. In the first experiment, germination behaviour of five lettuce cultivars (Year Round Cabbage, Americana Great Lakes, Great Lakes 659, Lucy Brown, and Crisp Cabbage) was evaluated under five levels of salt stress (0, 50, 100, 150 and 200 mM). In the second, two lettuce cultivars, one sensitive and one tolerant to salinity, submitted to six different combinations of NaCl and Na2SiO3. The germination (G), first germination count, germination speed index, mean germination time, and root and shoot length and dry weight were evaluated. A reduction in G was seen from 100 mM for all cultivars, with 'Lucy Brown' being the most tolerant, even under higher levels of NaCl. The 'Americana Great Lakes’ and 'Great Lakes 659' were the most sensitive to salinity. When silicon was added to the NaCl treatments, it was found that the effects of the salt stress were reduced, resulting in higher values for germination and the growth variables. Silicon reduced the detrimental effects of salt stress on the physiological quality of the seeds and the initial growth phase of the lettuce.