The priming of seeds is shown as a viable technique to improve germination, the growth of the radicle and plumule, and the seedling vigor index, which gives rise to seedlings with higher quality and tolerance to environmental growing conditions. Sodium selenite (Na2SeO3) and selenium nanoparticles (nSe) were used as priming media and postgermination biostimulation in seeds of jalapeño pepper, in concentrations of 1, 5, 10, 15, 20, 25, 30, 35, 40, and 45 mg L−1 for the two Se species, and control treatment. This research aimed to determine the priming response of jalapeño pepper regarding the germination percent, germination speed index, radicle length, plumule length, fresh weight, and seedling vigor index. The stimulation and phytotoxicity thresholds were also computed. The results showed a percentage of germination greater than 80% in all concentrations evaluated. Most variables of jalapeño pepper presented stimulation responses at Na2SeO3 doses lower than 5 mg L−1 and nSe doses lower than 15 mg L−1. The higher daily germination was favored by nSe on the fifth day compared to the sixth day of Na2SeO3; in addition, the higher cumulative germination occurred on the sixth day with nSe and on the eighth day with Na2SeO3. The use of low Na2SeO3 concentrations positively favors germination and the morphological traits of the shoots. Likewise, the use of Se in nanometric form was friendlier, that is, the degree of tolerance to Se was higher.