Grandpa Gohan, also referred to as just Gohan, is the adoptive Human grandfather of Goku until Goku turned into a Great Ape and accidently killed him. He is often referred to as "Grandpa" Gohan to separate him from Goku's son Gohan, named in honor of him. He along with the Ox-king was students of the Turtle Hermit Master Roshi.
Grandpa Gohan is a short, stubby old man with small dark eyes and a bushy white mustache and eyebrows and is also bald. He wears a Chinese martial arts uniform, which consists of a sleeveless orange jacket over a long sleeved black shirt, and wears a green hat.
Grandpa Gohan is a kind and loving man, kind enough to adopt Goku when he found him in the woods. It is likely much of Goku's personality and morality came from him. According to Goku, Grandpa Gohan had good manners and acted very well towards ladies. Grandpa Gohan may have been popular with the ladies, or perverted just like Master Roshi, because he says "I've got a lot of friends, and most of them are brunettes" in the Fortuneteller Baba Saga.
Dragon Ball Z