Unlike the other tougher greaser gangs in the Susan E. Hinton novel, The Outsiders, the Curtis brothers' gang is more like a family--
... just small bunches of friends who stick together... you take up for your buddies, no matter what they do. When you're a gang, you stick up for your members. If you don't stick up for them, stick together, make like brothers, it isn't a gang anymore. It's a pack.
The brothers--Darry, Sodapop and Ponyboy--have a genuine love of each other, in spite of Darry and Pony's constant bickering. Johnny Cade, whose parents virtually ignore him (except when his father is beating him), is like an extended member of the Curtis family; the same can be said of Two-Bit Matthews. Steve Randle is very close to Soda, working with him at the same gas station and double-dating as well. Like the Curtis' (whose parents are dead), Dallas Winston lives on his own; he and Johnny are particularly close.
Except for Dally, who grew up on the streets of New York and is "as wild as the boys in the downtown outfits, like Tim Shepard's gang," Ponyboy's gang is more of a brotherhood.