- "The Right Arm – if they're really against WCKD, maybe they can help us."
- — Thomas, Maze Runner: The Scorch Trials
- "Please don't fight them, Thomas!"
- — Teresa calls WCKD, resulting in the camp's invasion and the capture of some Immunes
The Right Arm is an organization opposed to WICKED. Their leader is Vince. They believe that the money that WICKED has been using in their search for a cure to the Flare would have been better spent in preventing the disease being spread across the planet, keeping more people healthy. The Right Arm has members in every remaining city.
Thomas, Minho, Brenda, and Jorge get a note from Gally shortly after arriving in Denver in The Death Cure. They visit him and he informs them that he is working with the Right Arm. They are kidnapped upon arriving back from the Crank Palace a few days later. They force the captives to take them to the leader of the Right Arm, for they discover it was they who kidnapped them. They meet Vince, who explains that they have been selling Immunes to WICKED so that when the time comes they can launch an attack. They send Thomas to WICKED so that he can plant a device in the WICKED Head Quarters, allowing the Right Arm to attack while no one is able to use weapons. However, Thomas realizes that they are planning to blow up the headquarters rather than just take over it, so he convinces the others to leave them and help evacuate the Immunes trapped inside.
In the Scorch Trials film, the Right Arm is portrayed quite differently. Rather than having a base in Denver, the group is surviving out in the wilds of the Scorch. Sonya and Harriet are also members. Thomas, the other remaining Gladers, Brenda, and Jorge meet the group, but WCKD finds them due to Teresa's betrayal and raids their camp that night. A battle ensues, and Minho, Aris, and Sonya end up being captured by WCKD. The film ends with Thomas and the others recovering from the battle and figuring out a plan of attack against WCKD.
In the Death Cure film, against the orders of the Right Arm resistance led by the newly sworn Vince, Thomas, Newt, and Frypan leave their camp base to rescue their immune friend Minho, who is being tested by the organization WCKD for a Flare cure. Heading for the "Last City" where WCKD's headquarters is located. The group make their way through a tunnel, only to be attacked by Cranks, humans zombified by the Flare. However, they are saved by Jorge and newcomer Brenda, who journey to the Last City with them. In the WCKD Tower, the serum created from Minho's blood is tested on a Flare-infected girl, which fails, to the frustration of WCKD's scientists. Gally takes them to see Lawrence, a rebellion leader for the infected, who grants Thomas, Newt, and Gally permission to enter the Last City through a secret entrance. Gally leads Thomas and Newt through to the city and then uses a telescope to spy on the WCKD Tower. Spotting Teresa, Gally tells Thomas that she can get them in, and Thomas gets Teresa to follow him into an alley where Gally captures her. Thomas and Gally take Teresa to an abandoned church where she agrees to help them, as long as they and Newt need to use her fingerprint to get inside the WCKD Tower. Teresa also removes the Gladers' trackers that WCKD put in them before they entered the Maze. Outside the tower, Gally finds Thomas, who has given Janson the middle finger, Newt, who had apparently been infected, and Minho, who is shocked to see that Gally is alive. Thomas sends Minho and Gally ahead before Newt gives him a necklace with a silver cylinder on the end before passing out. Teresa transmits her voice throughout the city, telling Thomas that his blood can save Newt and all that he needs to do is to return to WCKD. However, Newt regains consciousness, almost as a Crank, and attacks Thomas, begging for him to kill him. With no other option, Thomas mercifully stabs and kills Newt. Thomas, Minho, Gally, Frypan, Brenda, and Jorge reunite with Vince, the rest of the Immune teenagers, and the Right Arm, escaping to a safe haven that was revealed by Ava. There, Thomas discovers that the necklace Newt gave to him had a note concealed in it from him to Thomas. Still traumatized by Teresa's death, he reads the note, in which Newt tells him to look after himself and everyone, before thanking Thomas for being his friend.