Overgrowth syndromes, although rare, are diagnosed more frequently lately. Major progress, such as the identification of genetic causes, has recently enhanced the delineation of the characteristic and noncharacteristic manifestations, phenotype-genotype correlations and knowledge of the underlying pathophysiologic mechanisms. This review provides a summary of the most important overgrowth syndromes aiming to familiarize the treating physician with the cardinal clinical features involved in these syndromes that encompass overgrowth, but also have a variety of other clinical manifestations (neurologic, musculoskeletal, skin, and accompanying tumors).