- For the primary universe counterpart, see Simon Van Gelder.
- See Van Gelder for other articles with titles that contain, either by relationship or by coincidence, this character's surname.
In the mirror universe, Dr. Simon Van Gelder was a Terran male who served as the second-in-command of the Tantalus colony after he had dropped out of Starfleet Academy. While still at the Academy, Van Gelder assisted James T. Kirk in murdering an upperclassman named Sean Finnegan who had been bullying him.
In 2264, Van Gelder was visited by Kirk. He agreed to give Kirk a positive psychiatric review on the condition that Kirk helped him leave the colony so that he would not be implicated in Tristan Adams's attempts to actually rehabilitate people (which were contrary to official Imperial policy). Once Kirk agreed, Van Gelder started a prison revolt as a distraction and looted the store room before trying to leave. Unfortunately for Van Gelder, he was killed when Kirk discovered the Tantalus field and used it on him. (TOS - Mirror Universe short story: "The Greater Good")