The decrease in rainfall leads to a drastic reduction in corn production. Thus, the use of an algae-based biostimulant was studied to improve corn growth and production under water stress conditions. To this end, four water regimes (25, 50, 75 and 100% of field capacity), all coupled with the application of biostimulant or not, were applied to plants of three corn varieties in greenhouse potting soil. From sowing to harvest, growth, phenological and yield parameters were evaluated. The results of the ANOVA test revealed that the decrease in the water regime significantly slows down plant growth, reduces their chlorophyll content, grain yield, and accelerates plant phenology. However, the application of the biostimulant significantly improved yield and its components from 1000 to 1700 kg/ha; from 1200 to 1900 kg/ha and from 1200 to 2300 kg/ha respectively in the yellow, purple and white varieties. In addition, the biostimulant significantly (P ˂ 0.001) slowed down the effects of this decline through the maintenance of plant height, collar diameter, number of leaves, yield and accelerated phenology. In summary, the use of algae-based biostimulants could be an innovative solution to improve the resilience of maize crops to the challenges of increasing climate change, including drought.