ABSTRACT To test the differential effect of gender and regional belonging, we used a method based on the ingroup over-exclusion effect but taking into account both the gender of the participants and the stimuli. Two experiments were conducted to study the role of gender of participants in the categorization of ambiguous faces as humans or animals. According to the over-exclusion hypothesis, individuals protect their ingroup by excluding any individual who casts doubt on the humanity of the group. In our research, we took into account gender of participants and regional belonging, and the stimuli requiring assessment, including human, ape and ambiguous human/ape-like faces created through morphing procedure. Our results support the over-exclusion hypothesis, but only when participants do not share the same gender category with the target. Same-gender participants and stimuli annul the over-exclusion bias on the regional ingroup. These data are discussed in line with various theoretical hypotheses developed within the framework of the psychology of intergroup relations.