Openness has been identified as one of the personality traits with stronger association to creativity into the Five-Factor-model of personality. But what are the psychological mechanisms that relate Openness and creative performance? The present paper aims at responding to this question, exploring in particular whether the attentional processing of apparently irrelevant information (irrelevance processing) can act as a moderator within the relation between Openness and creativity. To this aim, a visual version of the Unusual Uses Task was developed and, using an eye-tracker methodology, the attentional processing of both information that is central to the task and information that is “apparently” irrelevant for its execution was measured. The results showed a moderating effect of irrelevance processing on the role of Openness in both creative achievement and originality of the uses produced by the participants, with creativity reaching higher levels in individuals who gave attention to irrelevant information and were characterized by a high level of Openness. These findings establish attentive processing as a central psychological mechanism to explain the relationship between Openness and creativity.