The purpose of the current investigation is to standardize the aqueous leaf extract of Coriandrum sativum L. with a high-performance thin-layer chromatography (HPTLC) method. The method involves the determination and validation of extract with quercetin as standard. Chromatography was performed on pre-coated silica gel G 60 F254 plate as the stationary phase with formic acid, ethyl acetate and toluene as the mobile phase in the ratio 1:4:5 (V/V). Identification and quantification were conducted optical densitometrically at 254 nm. The RF value of quercetin obtained for the standard as well as the leaf extract was found to be 0.50. The method was validated for intra-day and inter-day precision and accuracy. The accuracy of the method was established by a recovery study, with 98.04 ± 0.21% average recovery of quercetin. The lyophilized coriander extract samples contained 0.058 ± 0.02% quercetin. The HPTLC method resulted in the development of an accurate, precise, reproducible and pragmatic approach to standardize the aqueous leaf extract of C. sativum L.