Chemical fertilizer use efficiencies should be increased to reduce fertilizer quantities and potential negative impacts of excessive uses on soil and environmental health. Therefore, alternative soil nutrient sources are searched for and biological alternatives offer promising outcomes in this sense. In this study, effects of single, dual and triple combinations of phosphorous-solubilizing (Bacillus megatherium var. phosphaticum [ M-13]) a nd N -fixing b acteria ( Stenotrophomonas maltophilia [82] and Ralstonia pickettii [73]) treatments on plant growth, yield and yield component of barley were investigated and potential effects were compared with chemical fertilizers (N (80 kg ha^-1 N ), P (50 k g h a^-1 P₂0₅) and N+P (80 kg ha_-1 + 50 kg ha^-1 P₂0₅) and Control treatments. The longest grain filling period was obtained from Ralstonia pickettii, Stenotrophomonas maltophilia and Bacillus megatherium var. phosphaticum + Stenotrophomonas maltophilia bacteria treatments. The highest number of spikes per m², 1000-kernel weight, and test weight values were obtained from sole N treatments, the highest number of kernels per spike, protein content, grain yield, and biological yield from N+P treatments and the highest harvest index values from Ralstonia pickettii + Stenotrophomonas maltophilia treatments. In general, bacterial treatments resulted in significant changes in yield and yield parameters of barley and significant increases were achieved as compared to the Control.