Dragon Ball Gang is the name of the traveling team that Bulma and Goku assembled together during their first journey for the Dragon Balls. They traveled through the eastern half of Earth, finding the Dragon Balls and defeating forces of the Rabbit Mob and the Pilaf Gang.
The team officially formed when Goku agreed to go with Bulma on her quest for the Dragon Balls. They traveled past Mount Paozu and into Skull Valley where they met Turtle. Bulma was originally against the idea of taking the turtle back to the ocean, but ended up tagging along with them since she was defenseless without Goku. After a minor conflict against a Bear Thief Goku and Bulma returned the turtle back to the ocean where his master an old man named Master Roshi gave Bulma his Dragon Ball and Goku the Flying Nimbus as a reward.
Another member, Oolong, joined when Goku and Bulma saved Aru Village; although Bulma actually forced him to go. Then, along the way to Fire Mountain, they met the villainous Yamcha and Puar in Diablo Desert, who would become the member additions to the Dragon Ball Gang. Bulma, Oolong and Goku slept in the House-Wagon that night, and were attacked again by Yamcha and Puar in the morning. At Fire Mountain, they met the Ox-King and Chi-Chi, who would become Goku's wife several years later.
In the Tournament Saga, while training with Master Roshi, Goku met his best friend Krillin, and also Launch. While dealing with the Red Ribbon Army, Goku reunited with Bulma and some of the others until he decided to take down the army single handedly. Afterwards, the entire gang (sans Oolong and Launch) gathered at Fortuneteller Baba's Palace in order to do battle with her warriors as a price for her telling them where the final Dragon Ball is. Later, at the 22nd World Martial Arts Tournament, the gang met Tien Shinhan and Chiaotzu. In Dragon Ball Z, Goku is all grown up and "formed" a similar team, called the Z Fighters. There were both new members as well as returning team mates.