An high-performance TLC (HPTLC) method for the separation of boswellic acids, the active constituents in Boswellia serrata extract, has been developed and TLC of these compounds on silica by automated multiple development (AMD) using solvent gradients was performed. Enhancement of the separation of boswellic acids on HPTLC plates was carried out by AMD chromatography. Densitometric analysis of the developed plate was carried out to quantify the four boswellic acids. 11-Keto-beta-boswellic acid (KBA) and acetyl-11-keto-beta-boswellic acid (AKBA) were quantified by densitometric scanning of the developed plate at 254 nm. beta-Boswellic acid (BA) and acetyl-beta-boswellic acid (ABA) were quantified after derivatization with anisaldehyde sulfuric acid reagent at 560 nm. The AMD system provided a clean separation according to polarity for each of the four groups studied and good results were obtained. The proposed HPTLC method for the simultaneous quantification of the major boswellic acids BA, ABA, KBA, and AKBA was found to be simple, precise, specific, sensitive, and accurate and can be used for routine quality control and for the quantification of these compounds in plant materials. The study of market products revealed significant variations in the content of these pharmacologically active compounds in commercial samples.