Inquisitor is a legal title to denote a person or being who is an agent associated with an Inquisition.

Within Cardassian culture, Inquistor is a title of an educator who works at a university on Cardassia Prime. In the 24th century, Tekeny Ghemor's wife was an inquisitor at the Central University. (DS9: "Second Skin")

On Sarpeidon, officials of the Inquisitional Tribunal were known by this title (TOS: "All Our Yesterdays")