Readalikes for Among the Hidden (The Shadow Children series) by Margaret Peterson Haddix:
These are all science fiction set in the near future:
Applegate, Katherine. “Animorphs” series.
Bawden, Nina. Off the Road.
Beake, Lesley. Remembering Green.
Christopher, John. The White Mountains.
Clayton, Emma. The Roar.
Cooper, Susan. Green Boy.
Dashner, James. The Maze Runner.
Diamand, Emily. Raiders’ Ransom.
Diamand, Emily. Flood & Fire.
DuPrau, Jeanne. The City of Ember and sequels.
Falls, Kat. Dark Life.
Farmer, Nancy. The Ear, the Eye, and the Arm.
Hughes, Monica. Invitation to the Game.
Landon, Kristen. The Limit.
Lowry, Lois. The Giver and sequels.
Matas, Carol. The Edge of When.
McCann, Lisa. The Unwanteds.
Messner, Kate. Eye of the Storm.
Nelson, O.T. The Girl Who Owned a City.
Philbrick, W. Rodman. The Last Book in the Universe.
Sedgwick, Marcus. Floodland.
Service, Pamela. The Wizards of Wyrd World.
Stahler, David. Truesight.
Stead, Rebecca. First Light.
VanEekhout, Greg. The Boy at the End of the World.
Walsh, Jill Paton. The Green Book.
Penny Peck, San Jose State University, School of Library and Information Science