A rapid analytical method was developed and optimized to determine gluten content in bread. Existing gluten quantification methods were inappropriate for bread with high gluten content because they were optimized to analyze shallow gluten content. To overcome this problem, the first method of quantifying the gluten content in bread was developed by modifying the gluten analysis method in cereal grains. Heat-stable gliadin was selectively quantified for gluten quantification using high-performance liquid chromatography (HPLC), and gliadin peaks were separated using an Agilent SB-C8 column. The specificity, linearity, accuracy, precision, limit of detection (LOD), and limit of quantification (LOQ) were measured for validation. The calibration curve of gliadin had high linearity (R2 = 0.9996), and LOD and LOQ were 0.03 and 0.10 g/100 g, respectively. The relative standard deviation (RSD) values of intra- and inter-day precision were less than 2.49% and 1.54%, respectively. Recovery ranged from 90.73% to 93.87%, with RSD values less than 2.06%. These results indicate that the HPLC method for quantifying gluten in bakery products is efficient, reliable, and reproducible.