Aim The aim of this study was to evaluate magnetic resonance imaging findings of sphenoid sinus (SS), pituitary gland and related structures in patients with non-functioning pituitary adenoma (NFPA) and compare to a control group. Methods This study was conducted in a tertiary referral hospital between January 2018 and July 2020. Sixty-five patients diagnosed with NFPA and age- and gender-matched controls (n = 40) were included. Results The average age in the NFPA group was 37.46 +/- 11.2 years and in the control group was 41.97 +/- 14.88 years, and they did not differ significantly (P = .103). SS mucosal thickness greater than 1 mm was determined in a higher proportion of NFPA (67.7%) than in the control group (12.5%) (P < .001). A mucosal thickness greater than 3 mm was only present in the NFPA group (43.1%). The distance between optic nerves was significantly longer in the NFPA group compared with control (P < .001). There was a strong positive correlation between adenoma volume and distance between the two optic nerves (r = .728, P < .001). Also, there was a moderate positive correlation between adenoma volume and petrous intercarotid distance (ICD) (r = .561, P < .001) and a low positive correlation between adenoma volume and cavernous ICD (r = .408, P < .001). Conclusions The present study showed an association between NFPA and both SS mucosal thickening and increased distance between optic nerves. Also, our study demonstrated that there was a strong positive correlation between adenoma volume and distance between the two optic nerves.