Background: The structure of the frontal sinus varies greatly, and these differences influence the onset and progression of clinical diseases. Frontal sinus morphology is unique to each individual and may be used to properly identify people. Aim: The aim of this study is to evaluate the morphometric anatomical variations of the frontal sinus in adult Libyan people using a CT scan in relation to gender. Method and result: 147 patients (78 females and 69 males) were included in this study. Patients were divided into three groups regarding their frontal sinus pneumatization extent on the orbital roof: group 1 pneumatization (small), group 2 pneumatization (medium), and group 3 pneumatization (large). We found that the most common frontal sinus type is medium-sized (37.75 %), followed by the small (24.8%) and large (22.8%) types, respectively. There was no significant difference between the right and left sides in terms of frontal sinus type (P-value = 0,311). We recorded aplasia in 17.7% of all patients, which included (bilateral in 9.5%, left unilateral in 2% and right unilateral in 6.1%). In conclusion, we classified frontal sinuses using the categorization established by Stokovic et al. and showed that pneumatization patterns differ even between two opposite sides of the same individual.