Robert Shearman and Lars Pearson, in their book "Wanting to Believe: A Critical Guide to The X-Files, Millennium & The Lone Gunmen", rated the episode three stars out of five. The two compared the episode to "Musings of a Cigarette Smoking Man", but called it "throw away and charming". Shearman and Pearson criticized the episode for being "largely concerned in suggesting to the audience that the government is being conspiratorial ... five seasons into a hit series which has turned that argument into a cliche." Paula Vitaris from "Cinefantastique" gave the episode a positive review and awarded it three stars out of four. She wrote that, "'Unusual Suspects' is filler–but amusing filler". Vitaris further complimented the performance of Signy Coleman as Susanne Modeski, and called the return of "not-yet-dead" X as "welcome".