Orion slave girls were Orion females that were sold at slave markets. Orion slave girls were a much sought after commodity due to their sexual allure and appetites. (TOS: "The Cage"; ENT: "Bound")
Many Orion females sold as slaves were covert operatives seeking increase their personal wealth and satisfy their sexual desires. Some Orion females, however, were actual slaves.
In 2370, Candela Greene, a Orion/Human hybrid, was made the slave girl of a Romulan named Juraan. She would remain his slave for four years before escaping.
Vorina also served as a slave girl before turning to piracy.
In late 2382, Commander B'verk and Lieutenant Curtis Hogan saw an Orion slave girl at a Romulus night club. (Star Trek: Pioneer: "Night Club")