Fibrous dysplasia is one of the benign fibro-osseous lesions. It may have more common monostotic form (a single bone lesion) or polyostotic form (multiple bone lesions) which is less common and may be associated with McCune-Albright Syndrome (that is hyperfunctioning endocrinopathies and hyperpigmented skin lesions). Fibrous dysplasia is common in its monostotic form in the maxillofacial skeleton. What is essential in a dental practice of each clinicist is not only knowledge of classification of diseases of the jaws but also being able to differentiate them, make a proper diagnosis beforehand for a subsequent suitable treatment. The aim of this article is to outline the differences between FD, the most common lesions such as ossifying fibroma, but also other nosologic entities of this heterogeneous group of diseases.