© 2019 Society of Pharmaceutical Sciences of Ankara (FABAD). All rights reserved.This study aims to the quantitative analysis of tannic acid in different extracts of Quercus species growing in Turkey. For this purpose, the quantitative analysis of tannic acid was performed in two oak galls (Q.infectoria subsp. infectoria and subsp. boissieri) growing in Turkey by using of High Performance Liquid Chromatography (HPLC) method. Four different solvents were used for extraction procedure. So, tannic acid contents were determined in 96% ethanolic extracts (30.852-81.012 mg/g), 80% ethanolic extracts (43.898-127.683 mg/g), 70% acetone extracts (3.064-67.200 mg/g) and extracts with mixture of diethylether: ethanol: water (0.016-0.112 mg/g) for Quercus infectoria subsp. boissieri and Q. infectoria subsp.infectoria galls, respectively. The most abundant tannic acid has been reported as 127.683 mg/g in the 80% ethanolic extract of Quercus infectoria subsp. infectoria. The limits of detection and quantification were measured as 1.5 ppm and 4.95 ppm, respectively. This is the first study on the quantitative determination of tannic acid for two subspecies of Quercus infectoria (subsp. infectoria and subsp. boissieri) growing in Turkey in literature.