Considering current agricultural practices and certain indicators, it is impossible to comment on sustainability of these practices. Chemical fertilizers are among such unsustainable practices. Because of increasing mineral fertilizer costs and negative environmental impacts of these fertilizers, the interest in biological nitrogen fixation is increasing within the scope of sustainable agriculture (without significant yield losses). Therefore, effects of phosphorus-solubilizing (Bacillus megatherium var. phosphaticum [M-13]) and nitrogen-fixing (Stenotrophomonas maltophilia  and Ralstonia pickettii ) bacteria and chemical fertilizer treatments on wheat yield and quality parameters were compared with control treatment in present study. Significant differences were observed among treatments with regard to entire parameters. Although the best results were observed in chemical fertilizer treatments, single, dual, and triple bacteria combinations yielded significant increases in grain filling period, number of spikes per square meter, number of kernels per spike, 1000-kernel weight, biological yield, grain yield, grain protein ratio, plant protein ratios in flowering, and physiological maturity periods. Based on these findings and considering the M-13 + 73 + 82 triple bacteria combination with regard to grain yield and protein ratios, it may be concluded that such treatments may reduce the amount of fertilizer to be used by 20%. Among the dual bacteria treatments, 73 + 82 and 82 + M-13 were found to be advantageous with regard to grain filling period, 73 + M-13 with regard to 1000-kernel weight and grain protein ratio, and M-13 + 73 and M-13 + 82 with regard to plant protein ratio in the physiological maturity period.