A high-performance thin-layer chromatography (HPTLC) method for the analysis of seven fructooligosaccharides (FOS, DP3-9) in Morinda officinalis How. (M. officinalis) and Arctium lappa Linn. (A. lappa) has been established. The chromatographic analysis was developed twice with a mobile phase consisting of n-butanol-isopropanol-water-acetic acid in volume composition 7:5:2:1 and obtained on silica gel 60 plate. The chromatograms were visualized with 1-naphthol-sulfuric acid reagent. Densitometric detection was performed in visible light at 585 nm for seven FOS. The analytical range was set as 131-1050 ng for FOS. Calibration was linear within the selected range (R > 0.9901). The developed method was applied for the simultaneous determination of seven FOS in M. officinalis and A. lappa. The results indicated that the contents of FOS are variant in different M. officinalis samples, but constant in different A. lappa samples. This HPTLC method was found to be simple, stable, and reproducible. Hence, the developed HPTLC method would be an important tool for the quality control of FOS in medicinal plants.