Grady Sizemore III (born August 2, 1982) is a Major League Baseball center fielder who currently plays for the Cleveland Indians. A fan favorite in Cleveland, Sizemore was acquired from the Montreal Expos in 2002 along with Brandon Phillips, Cliff Lee, and Lee Stevens in exchange for Bartolo Colón and Tim Drew. Sizemore is regarded as being a "five-tool talent" – possessing the talent to hit for power and average, being an above average defender, and having above average arm strength and above average speed.

Sizemore graduated from Cascade High School in Everett, Washington, in 2000. A high school star in football, basketball, and baseball, Sizemore signed a letter of intent to play football and baseball at the University of Washington. At the time of his high school graduation, Sizemore was Cascade's all-time leader in rushing yards with 3,081 yards and interceptions with 16.

He is biracial, his mother Donna is white, while his father, Grady II is black. He has a younger brother named Corey.