Benzylacetone is released by heated agarwood, when inhaled it has a potent effect on reducing the locomotor activity of mice. This study investigated the relationships between the sedative activities of benzylacetone and its derivatives as well as the chemical structures of these compounds by comparing their activities in mice treated with a series of compounds. It was demonstrated that benzylacetone-like compounds had sedative activities and their intensities varied depending on the functional group in the carbon chain, the substituent in the benzene ring, and their combinations. A quantitative structure–activity relationship study was carried out using a series of 17 benzylacetone derivatives to determine the structural features with significant for the sedative activity.