David Gerrold is an American science fiction screenwriter and novelist. He wrote the script for the original Star Trek episode "The Trouble with Tribbles", created the Sleestak race on the TV series Land of the Lost, and wrote the novelette "The Martian Child", which won both Hugo and Nebula Awards, and was adapted into a 2007 film starring John Cusack.

"The Trouble with Tribbles" is the fifteenth episode of the second season of the American science fiction television series Star Trek. Written by David Gerrold and directed by Joseph Pevney, it was first broadcast on December 29, 1967. In this comic episode, the starship Enterprise visits a space station that soon becomes overwhelmed by rapidly reproducing small furry creatures called "tribbles."