This study investigates the effects of different biostimulants on the yield and performance of *Rosmarinus officinalis* L. (rosemary) in an organic agricultural system. Four commercial biostimulant formulations—based on *Eklonia maxima*, *Ascophyllum nodosum*, fulvic acids, and protein hydrolysates—were tested against water as a control. The study was conducted over two growing seasons in Sicily, Italy, with a focus on rainfed conditions. Six foliar applications of biostimulants were performed, and various morphological and productive parameters were measured at harvest. The results showed that all biostimulant treatments significantly affected the parameters studied. Fulvic acids and protein hydrolysates resulted in the highest fresh and dry biomass yields, with values 60% higher than the control. The highest essential oil (EO) content was observed in the control plants, while the lowest was in those treated with fulvic acids. In terms of EO yield, the highest values were obtained from *Eklonia maxima* and protein hydrolysate treatments. The study highlights the potential of biostimulants to enhance the yield and performance of rosemary in organic farming systems, providing valuable insights for organic growers and researchers.This study investigates the effects of different biostimulants on the yield and performance of *Rosmarinus officinalis* L. (rosemary) in an organic agricultural system. Four commercial biostimulant formulations—based on *Eklonia maxima*, *Ascophyllum nodosum*, fulvic acids, and protein hydrolysates—were tested against water as a control. The study was conducted over two growing seasons in Sicily, Italy, with a focus on rainfed conditions. Six foliar applications of biostimulants were performed, and various morphological and productive parameters were measured at harvest. The results showed that all biostimulant treatments significantly affected the parameters studied. Fulvic acids and protein hydrolysates resulted in the highest fresh and dry biomass yields, with values 60% higher than the control. The highest essential oil (EO) content was observed in the control plants, while the lowest was in those treated with fulvic acids. In terms of EO yield, the highest values were obtained from *Eklonia maxima* and protein hydrolysate treatments. The study highlights the potential of biostimulants to enhance the yield and performance of rosemary in organic farming systems, providing valuable insights for organic growers and researchers.