The monoterpenic composition of the essential oil of oleo-gum-resin Ferula gummosa Boiss from Iran was studied by GC×GC–ToFMS. This study allowed to tentatively identify 130 monoterpenic compounds including 24 hydrocarbons, 52 alcohols, 4 ethers, 20 aldehydes, 8 oxides, 18 ketones, 1 furan and 3 epoxides, from which only 25 were reported before in this species. Furthermore, while previous studies identified terpenic hydrocarbons such as β- and α-pinene as the most abundant monoterpenes, in the present study monoterpene alcohols as myrtenol, mentha-1,8-dien-7-ol, two pinocarveol isomers and mentha-1,5-dien-8-ol were the predominant components. GC×GC–ToFMS analysis allowed achieving a deeper characterization of the monoterpenic composition of F. gummosa, which may contribute to the increase of the value of this biomass plant material as a source of monoterpenic compounds. Moreover, this approach allows a more efficient quality control for existent applications and to prevent adulterations, promoting market confidence.