Giant cell lesions in oral tissues occur as extraosseous lesions of soft tissues and intraosseous masses within the jaws. The CGCG was classified as reactive proliferative lesion and a neoplastic lesion due to its biological behavior and histopathological features. The study was carried out on forty paraffin blocks divided into aggressive and non-aggressive according to clinic-radiographical data. Hematoxylin and eosin staining was performed and then examined by light microscope for evaluation of the studied cases for confirmation of the diagnosis and for evaluation of cellular cannibalism. This study aimed to evaluate cellular cannibalism, angiogenicity and myofibroblastic activity in aggressive and non-aggressive CGCG lesions and assess the correlation between these parameters with the aggressiveness of these lesions. The results of the study showed a high level of significant difference between aggressive and non-aggressive CGCG lesions as regard cellular cannibalism, microvascular density using CD-34 and myofibroblastic activity using α-SMA. In addition, a high positive correlation was found between cellular cannibalism, CD-34 and α-SMA expression.From the current study, it can be concluded that: Findings as even distribution of giant cells with clear zones in most cases in addition to cellular cannibalism, which found in all cases might indicate a neoplastic nature of CGCG lesion rather a reactive lesion. In addition, cellular cannibalism can be used as a simple histopathological predictor of the behavior of CGCG lesions using H and E stain. There is a reciprocal relationship found between cellular cannibalism, angiogenicity and myofibroblastic differentiation where their high representation indicate aggressiveness of CGCG lesion.The higher prevalence of cellular cannibalism, angiogenicity and myofibroblastic activity might be used to anticipate the behavior of the lesion that make the follow up a mandatory issue in selected cases to give attention for recurrent cases.