A simple, rapid, and effective high-performance thin-layer chromatographic method has been developed for the analysis and quantitative determination of ellagic acid, gallic acid, and methyl gallate in the galls of Quercus infectoria Olivier. Analysis was performed on silica gel G F254 TLC plates with toluene–ethyl acetate–formic acid (6:4.5:2, volume ratio) as the mobile phase. Densitometric detection was performed at 300 nm. The method was validated for linearity, precision, stability, recovery, and robustness. The limits of detection (LOD) and quantification (LOQ) were determined. The calibration curves showed a good linearity for ellagic acid, gallic acid, and methyl gallate with correlation coefficients of 0.9995, 0.9997, and 0.9996, respectively. The LOD and LOQ values were in the nanogram range for all three compounds. The average recovery was >96%. The amounts of ellagic acid, gallic acid, and methyl gallate in the galls of Q. infectoria were determined by using calibration graphs. The developed me...