Giant cell is a generalized term for the cell that appears larger in size as compared to the other cells when observed under microscope. Cells with more than one nuclei are known as multinucleated giant cell. Multinucleated giant cells are called as polykaryocytes or syncytium. These cells are large, huge and often phagocytic. These were first reported in tuberculous granulomas by Rokitansky and Langhans in 1868. Giant cell lesions in the oral tissues occur as intraosseous growth within the jaws and as extra bony lesions in the soft tissues. The intrabony lesion comprises the giant cell tumor of bone, the giant cell granuloma or the focal giant cell lesion or brown tumor of hyperparathyroidism. The soft tissue giant cell lesion is the giant cell epulis or peripheral giant cell granuloma. Diagnosis of many lesions of the oral cavity is challenging to most clinicians because of their uncommon prevalence. A number of cystic, metabolic, osteodystrophic, microbial, tumour and tumour like lesions of the oral cavity present with characteristic giant cell lesions; which makes their diagnosis and study simpler.