Endophytic bacteria have great potential for improving the growth and productivity of crop plants. However, individual or combined endophytic bacterial strains (consortia) and their application method had a significant impact on their efficacy in improving crop growth and productivity. In this regard, the present study was conducted to explore the potential of the plant growth-promoting endophytic bacterial strains (PsJN, MN17, and MW4C) to improve the growth, yield, and physiological and biochemical attributes of flaxseed through seed and foliar inoculation methods. The inoculated and un-inoculated (control) seeds of the flaxseed cultivar were sown in pots under controlled conditions. The bacterial inoculum was applied to the potting seeds and plants, while the control was treated with 10% tryptic soy broth. The study findings revealed that the MW4C strain alone and in consortium performed better under the seed application method. The consortium significantly increased fresh shoot-root biomass (1.82 g and 0.84 g) and yield-seed weight (3.32 g) as compared to the control. Likewise, the consortium enhanced the biochemical attributes, i.e., protein, flavonoids, and phenolic concentrations to approximately 78.16, 174.04, and 21.66 mg kg(-1) FW, respectively, under the seed inoculation method. However, our results suggest that the selected bacterial strains improved the growth, yield, and physiological and biochemical index of flaxseed. Inoculation of endophytic bacteria significantly improved the growth, yield, and physiological and biochemical properties of flaxseed. The consortium applied through the seed inoculation method could be considered a potential biofertilizer technology for improved growth and productivity of flaxseed.