In this research, a series of experiments was carried out with two sunflower (Helianthus annuus L.) hybrids, Luka and Apolon, by germinating seeds on filter paper under controlled conditions in a climate chamber, as well as with hybrid Luka and his parental lines, in a field conditions by germinating seed in pots filled with the soil. The aim of the research was to determine the physiological role of hydrogen sulfide (H2S) in seedlings grown from seeds previously primed in sodium hydrosulfide (NaHS) solutions and exposed to drought stress conditions during germination. In an experiment under controlled conditions, increasing the level of osmotic stress by applying increasing concentrations of polyethylene glycol (PEG) 6000 reduced seed vigor in both tested hybrids, and the most prominent positive effect of pre-sowing seed priming with a hydrogen sulfide donor was determined at low (2.5% PEG) and medium (5% PEG) level of osmotic stress. In a field experiment, seed priming with NaHS solution resulted in maintaining a high percentage of germination in the hybrid Luka and both parental lines grown under drought stress initiated by soil saturation with water up to 30% of the field water capacity (FWC). The most prominent positive effect of NaHS on the increase in germination, mass of the aerial part and leaves under conditions of drought stress was determined in the maternal line, and the response to osmopriming depended on the genotype in general. Also, seed priming with NaHS did not result with stimulation of the enzymatic antioxidant defense mechanism. The obtained results of this research can provide future guidelines for the selection and breeding process with the aim of increasing sunflower drought resistance, which is of great importance for the production of this strategically important oil crop in times of severe climate change.