The odontogenic keratocyst (OKC) is a benign intraosseous cyst of the odontogenic origin, characterized by an aggressive behavior with a relatively high recurrence rate.OKC is mostly presented at the 2nd and 3rd decades and predominantly affect males. It affects mandible more than maxilla and is frequently found at the angle of mandible. OKC can clinically and radiographically mimic other benign and less aggressive lesions. It is therefore important to differentiate them from other cysts and tumors, for a proper treatment and reduction of recurrences.We report the case of a 19-year-old woman who presented with a swelling in left mandible. The clinicaland radiographicfeatures were in favor of a radicular cyst.Histological examination, however, contradicted this diagnosis, indicating a case of OKC.