This paper analyses student cross-assessment with a gender perspective in three different courses along several academic years in an engineering school in Spain. The aim of this study is to contribute to a wider understanding of the hidden effect of gender in higher education by testing if gender has any effect on the way students assess others and themselves. Previous research has demonstrated sex differences in self-image and self-confidence, which are both closely related to self-esteem and same- and other-sex esteem. It follows that gender effects might be expected in investigations on peer and self-assessment (PSA), as both techniques are closely linked to self-image and self-confidence. But a critical review of the literature on PSA with a gender perspective reveals that findings on this field are inconclusive, thus more research is needed. The analysis of the results of our study reveals that women judge themselves too harshly. As the literature on PSA does not show great concern for gender issues, some tentative suggestions are proposed to support PSA with gender-awareness sessions.