<p>Concealed information detection is the act of identifying whether someone is purposefully withholding or concealing the information. Although several different methods have been applied, there has been a current focus on eye-tracking, specifically fixation-based measurements, as a facilitating technique in the detection of deceivers. With an emphasis on the familiarity effect, studies have examined eye gaze patterns to distinguish between guilty individuals who have prior knowledge of crimes and innocent ones. The purpose of this paper is to determine whether eye movements can be used as an indicator for information concealment and then investigate the possible effects of familiarity and emotional affinity. A total of 55 healthy participants (35 females and 20 males; mean age: 22.8 years) were presented with a set of four faces. One of the faces was familiar (newly learned, well-known, or personally familiar), while the other faces were novel. Participants were instructed to conceal or reveal prior knowledge they had. The results showed that familiar faces tended to trigger longer fixation durations, and more fixation counts in the truth condition. Moreover, the impacts were more apparent on the faces that were personally familiar. These results show that eye movement patterns are highly modulated by personal familiarity, and they propose that eye-tracking for the concealed information detection should take this variable into account in future applications.</p>