Summary Background: Aneurysmal bone cyst is an expansile bone lesion, non-neoplastic in nature, occurring most commonly in long bones. It is uncommon in facial bones and exceptionally rare in ethmoid bone. Ten cases of aneurysmal bone cysts of ethmoid bone have been reported so far. Case Report: A young adolescent presented with decreased vision and pain in the right eye. MRI revealed an expansile lesion having conspicuous fluid levels with a multiloculated appearance in the right ethmoid bone extending to the right orbit. CT was done to characterize better bone details. Both biopsy of the lesion and histopathology of resected specimen confirmed aneurysmal bone cyst. Conclusions: A characteristic appearance on MRI and CT examinations helped to confidently diagnose a relatively common lesion in an exceedingly rare location.