Introduction: A recent study by Cheval et al (J Sex Med 2016;13:825e834) found that individuals high in homophobia look significantly less long at sex-related photographs, regardless of their nature (ie, homosexual or heterosexual). Because viewing time is under some conscious control, this result could indicate that individuals high in homophobia have a low sexual interest in any sexual stimuli or are consciously motivated to avoid sexual material in line with their conscious values. Aim: To determine the mechanism underlying shorter viewing time of sex-related photographs in individuals high in homophobia using pupil dilatation, which is considered a spontaneous, unconscious, and uncontrollable index of sexual interest. Methods: Heterosexual men (N ¼ 36) completed a questionnaire assessing their level of homo-negativity and then performed a picture-viewing task with simultaneous eye-tracking recording to assess their pupillary responses to the presentation of sexually related or neutral photographs. Main Outcome Measures: Non-linear mixed models were carried out to fit the individual non-linear trajectories of pupillary reaction. Different parameters were obtained including the final asymptote of the pupillary response. Results: Results showed that the final pupil size of men high in homophobia increased significantly less to the presentation of sex-related images (ie, heterosexual and homosexual) than the pupil size of men low in homophobia. In contrast, no significant difference in the final pupil size reaction toward homosexual images (vs heterosexual images) emerged between men high and men low in homophobia. Conclusion: Theoretically, these findings reinforce the necessity to consider that homophobia might reflect concerns about sexuality in general and not homosexuality in particular.