This study investigates gender differences in perceptions of body weight. Previous research has found significant gender differences in perceived weight-level, but less is known about weight perceptions of the opposite gender. Based on Danish survey data (859 women and 160 men), the discrepancy between BMI weight-level and self-perceived weight-level is estimated as well as the perception of one’s partner’s weight-level. Two main empirical conclusions emerge. First, there are significant gender differences in weight assessment. Whereas women assess weight according to the standardized BMI weight-levels for both genders, men assess weight according to gender. The weight-level of men is often underestimated by men themselves, but both men and women tend to overestimate the weight-level of women in the lower BMI deciles compared to standardized BMI weight-levels. Second, there is greater underestimation of weight-levels for individuals in the higher BMI – especially regarding weight perceptions of the opposite gender. These findings are discussed within a framework of socio-cultural theory of body image and gendered relations.