Abstract The composition of essential oils of three Sideritis species was investigated by GC and GC/MS. It was found that the oil of S. syriaca L. contained a high percentage of myrcene (50.5%), while sesquiterpenes dominated in the oils of S. scardica Griseb and S. moniana L. The major components in S. scardica oil were Î²-caryophyllene (18.8%) and nerolidol (12.1%), while germacrene D (41.1%) and bicyclogermacrene (10.9%) were the principal constituents of S. montana oil.