Within in the broad spectrum of disease that can affect the paranasal sinuses is a class of benign bony abnormalities known collectively as fibro-osseous lesions. Fibrous dysplasia, ossifying fibroma, and osteoma are three distinct entities that lie along a continuum from the least to the most bony content. They have similar appearance and makeup; however, their clinical implications vary. This article focuses primarily on sinonasal osteomas, with less emphasis on fibrous dysplasia and ossifying fibroma.