Colonel Phillip Green is a villain from the Star Trek universe. He is introduced in the TOS episode "The Savage Curtain."

Green first was portrayed by Phillip Pine and then later by Steve Rankin.

In the 2260s, Captain James T. Kirk and Spock find themselves battling duplicates of several of the most evil and brutal dictators from throughout time and space. Among these individuals is Colonel Green, who is said to have led a genocidal war on Earth in the mid-21st century and whose actions led to the deaths of millions of people. No further details about this war are given, although the Green re-creation expresses the original's ideas about the rules of warfare (he is reluctant to negotiate with anyone, except where it might personally benefit him). Also, Kirk and Spock point out that Green was fond of turning against his own allies whenever it suited him, and that he tended to strike at his enemies in the midst of conducting treaty negotiations.

The Star Trek: Enterprise episode "Demons" confirms a popular fanon speculation: the war that Green was involved with was World War III. Green was a leader of a major faction - possibly the Optimum Movement - during the war, and the group's actions directly led to 37 million deaths. After the war, Green killed hundreds of thousands of victims of radiation poisoning in order to prevent their future mutant offspring from contaminating the human genome. Despite Green's claims that the operation was "humanitarian," this eugenicist action was labeled as genocidal by future historians. Green's ultimate fate still remains unknown.

Green's first name is revealed on a computer readout screen in the Star Trek: Enterprise episode "In a Mirror, Darkly."