Group B is a second group who particpated in the Trials. The Gladers only discovered this when they met Aris at the beginning of The Scorch Trials. Group B was composed almost entirely of girls, with Aris being the only boy. The leaders were Harriet and Sonya until Teresa arrived. Each member of Group B appears to match up to one of the Gladers, and the experiences of the two groups in the Maze appear to have been extremely similar. One major difference was that Rachel was killed by Gally's equivalent in Group B, but in the Gladers, Chuck jumped in the way of the knife when Thomas should have been killed.They escaped from the Maze three days faster and lost less members than the Gladers, which the girls appear to be proud of. It does show that they are fairly capable.
Before Group B began the Scorch Trials, they were told by Janson that they must kill Thomas if they wished to receive the cure when they arrived at the Safe Haven. They were allowed to travel through underground tunnels through the Scorch, while the Gladers were forced to travel overland in the burning sun. After they ambushed the Gladers, took Thomas and dragged him up into the mountain pass, Thomas convinced them not to kill him. Group B and the Gladers met up at the Safe Haven, and they fought together against the Bulb Monsters.