Optimization of blending ratios of sorghum, rice, and teff flours supplemented with flaxseed flour for better quality injera making, although best quality injera is obtained from pure teff flour. In sorghum flour injera has observed texture quality drawbacks. The objective of this research work was to investigate the effects of sorghum(43-50%), rice (20-27%), teff (23-30%, and 3% supplemented of flaxseed flour on the overall better acceptable quality of injera making using D-optimal mixture design. The study response parameters were analyzed under standard AOAC and AACC methods and datas interpreted by minitab software 19.2 version, and also conduct one-way and two-way ANOVA depending on factors, its mean comparisons analyzed by tukey’s pairwaise comparison method. The 100% sorghum and teff flour injera as control and the blended injera product analyzed values;protein (9.0-9.3%), fiber (2.4-4.5%), carbohydrate (81.39-83.67%), energy (388.40-398.26 kcal/100g), phytate (175.66-177.93 mg/100g), total phenol (3.03-5.39 mg/100g), condensed tannin (0.00-0.17 mg/100g). The mineral iron and zinc content (12.13-16.17 mg/100g), 2.16-3.94 mg/100g), and its sensory score overall acceptability of injera (2.33-4.22) using five-point hedonic scale, respectively. During the storage duration periods of day-0,2,and 4 between each blended injera product, the yeast-mold and total bacteria load didn’t shown a significance difference (p<0.05), but shown a significance difference (p<0.05) between 100% sorghum flour injera at day-6 storage period in yeast-mold and total bacterial load. In conclusion, blending of cereal grains with flaxseed flour supplementation improved textural qualities with acceptable sensory characteristics of sorghum-based injera, which is comparable in teff injera. During the optimization process, the overall optimum point was found in a blended ratio of 50% sorghum, 20% rice, and 30% teff flours with a 3% flaxseed flour supplemented. It has (9.30%) protein, (3.01%) fiber, (83.16%) carbohydrate, (393.24 kcal/100g) energy, (13.99 mg/100g) iron, (3.78mg/100g) zinc, (4.06 mg/100g) overall acceptability, respectively with overall desirability of 0.9474. So, as an industry or household level flaxseed flour is an emerging functional food to recommended mixing with grains to optimize consumer overall nutritional acceptabilit quality injera making.