Seed bio-priming applications with plant growth promoting rhizobacteria (PGPR) have been widely used recently to improve germination and seedling growth. Therefore, the aim of this study was to investigate the effects of bio-priming with different bacterial strains on germination and seedling development of Italian ryegrass seeds. The sterilized seeds of the Elif variety (Lolium multiflorum Lam) were inoculated with nine different bacterial strains belonging to Bacillus species (108 cfu/mL bacterial suspension) for 15 min at 120 rpm and then dried at room temperature. The treated seeds were germinated in petri dishes with 25 seeds between 3 filter papers at 22 ±2 ˚C. The study was carried out in a completely randomized design with three replications. As a result of the study, no significant difference was obtained between the treatments in germination percentage and root length, but it was determined that SY2 and SY5 (Bacillus isolates) showed superior performance compared to the control in terms of shoot length and seedling fresh and dry weights.