After the underlying tech for M3GAN is stolen and misused by a powerful defense contractor to create a military-grade weapon known as Amelia, M3GAN's creator Gemma realizes that the only option is to resurrect M3GAN and give her a few upgrades, making her faster, stronger, and more lethal.
| Gemma | Allison Williams |
| Cady | Violet McGraw |
| M3GAN | Amie Donald |
| Christian Bradley | Aristotle Athari |
| M3GAN (voice) | Jenna Davis |
| Cole | Brian Jordan Alvarez |
| Tess | Jen Van Epps |
| AMELIA | Ivanna Sakhno |
| Agent Tim Sattler | Timm Sharp |
| Alton Appleton | Jemaine Clement |
| Naveen Tripathi | Mayen Mehta |
| Niles Keller | Mark Mitchinson |
| Moxie (voice) | Fryda Wolff |
| Agent Murphy | Luke Hawker |
| Agent Novak | Ben Van Lier |
| Agent Silva | Niwa Whatuira |
| Xenox Parc Guard | Mike Edward |
| Xenox Parc Worker | Michael Ravlic |
| Dock Manager | Byron Coll |
| Secretary Shelly Voss | Jacque Drew |
| Comms Officer | Paul Waggott |
| Ambassador Ling | Gary Young |
| General Hurst | James Gaylyn |
| Commander | Omar Al-Sobky |
| Mercenary #1 | Ahmed Youssef |
| Mercenary #2 | Ara Raad |
| Jonker | Barnie Duncan |
| Panelist | Steven Logan |
| Tour Guide | Jim McLarty |
| Cop #1 | Glen-Paul Waru |
| Cop #2 | Ryan Lampp |
| News Anchor #1 | Richard Lambeth |
| News Anchor #2 | Serena Cotton |
| News Anchor #3 | Jamie Irvine |
| Technician | Shervonne Grierson |
| Teacher | Simon Eskow |
| 911 Operator | Gerard Johnstone |
| Tiffany | Erika Camacho |
| Sapphire | Zara Nausbaum |
| Self | Hallie Jackson |
| Tech Reporter | Shanti Tucker |
| Comms Assist | Martin Richard |
| Robot Dancer | Isabella Lucia Goff |
| Robot Model | Gigi Holroyd |
| Kurt (archive footage) (uncredited) | Stephane Garneau-Monten |
| Excited Atendee | Quinn Sugrue |
| Background Performer | Rylee Arnold |
