Purpose: In the present study, we attempted to determine whether ultrasonic elastography (USE) evaluation can be used in a diagnosis of optic neuritis (ON). Materials and Methods: Thirteen patients who each had one normal eye and one eye with a diagnosis of ON were included in the study. Ultrasonography (US) and USE examinations were performed on the affected and non-affected eyes of all participants. Optic nerve and adjacent fat tissue regions at the same depth were selected, and USE measurements were obtained. The optic nerve diameter was measured in both normal and affected eyes. Results: The mean USE values for the optic nerve were 2.58 +/- 0.50 m/s in ON eyes and 1.91 +/- 0.39 m/s in normal eyes (p = 0.001). The mean USE values for the optic-nerve adjacent tissue were 2.26 +/- 0.45 m/s in ON eyes and 1.77 +/- 0.22 m/s in normal eyes (p = 0.001). The mean optic-nerve diameter was 3.80 +/- 1.09 mm in ON eyes and 3.28 +/- 0.98 mm in normal eyes (p = 0.005). Conclusions: USE may be considered an accessible, safe technique for the detection of significant optic-nerve tissue stiffness in ON and may be used an adjunctive tool for confirming this diagnosis.