In the X-Men comic books, the Morlocks were mutants who could not 'pass' as normal who created a new society in a vast network of abandoned interconnected tunnels beneath New York City. The X-Men were alerted to the existence of the Morlocks after Callisto kidnapped the X-Man Angel, intending to make him her mate. Storm defeated Callisto in hand-to-hand combat, rescuing Angel and becoming the de facto leader of the Morlocks.

Notable Morlocks include Callisto, Caliban , Annalee , Erg , Beautiful Dreamer , Ape , Healer , Sunder , Plague , Skids, Tar Baby , Masque , Leech and Marrow.

Most of the Morlocks were slaughtered by Mister Sinister's henchmen, the Marauders, in the Morlock Massacre or Mutant Massacre, and the survivors later moved to Gene Nation, located in a parallel dimension . (Callisto, Leech and Marrow are survivors of the massacre.) A later retcon made them the failed creations of the Dark Beast.

The Marvel Comics Morlocks were named after the Morlocks in H.G. Wells' The Time Machine.