Gigantism, also known as giantism (from Greek γίγας gigas, "giant", plural γίγαντες gigantes), is a condition characterized by excessive growth and height significantly above average. In humans, this condition is caused by over-production of growth hormone in childhood before the long bone epiphyses closes resulting in persons between 7 feet (2.13 m) and 9 feet (2.74 m) in height.

The term is typically applied to those whose height is not just in the upper 1% of the population but several standard deviations above mean for persons of the same sex, age, and ethnic ancestry. The term is seldom applied to those who are simply "tall" or "above average" whose heights appear to be the healthy result of normal genetics and nutrition. Gigantism is usually caused by a tumor on the pituitary gland of the brain. It causes growth of the hands, face, and feet. In some cases the condition can be passed on genetically through a mutated gene.

Other names somewhat obsolete for this pathology are (Greek: hyper over the normal level; soma body) and somatomegaly (Greek; soma body, genitive somatos of the body; megas, gen. megalou great). In the past, while many of them were social outcasts because of their height, some (usually unintentionally) found employment in Friedrich Wilhelm I's famous Potsdam Giants regiment.

George Kenneth "Ken" Griffey, Jr. (born November 21, 1969), nicknamed "Junior" and "The Kid", is an American former professional baseball outfielder and designated hitter. Griffey was both one of the most prolific home run hitters and best defensive players in baseball history, sixth on the list of most career home runs, and is tied for the record of most consecutive games with a home run (8 games, tied with Don Mattingly and Dale Long). Griffey, playing for the Seattle Mariners in two separate tenures, Cincinnati Reds and the Chicago White Sox, won 10 Gold Glove awards and appeared in 13 All-Star games. Upon his retirement, the Associated Press noted: "In his prime, Ken Griffey Jr. was unanimously considered the best player in baseball."

Throughout his major league baseball career, Griffey was a popular player and a fan favorite around the league. Griffey attained widespread recognition by signing lucrative deals with companies of international prominence like Nike and Nintendo (owners of the Mariners); his popularity reflected well upon MLB and is credited by some with helping restore its image after the 1994 labor dispute. He currently works in the Mariners' front office as a special consultant. Griffey is one of only 29 players in baseball history to date to have appeared in Major League games in four different calendar decades. He is the son of former MLB player Ken Griffey, Sr.