Fear of negative evaluation has been linked with weight/shape concerns among adults, however, similar research among adolescents is lacking. We investigated the relationship between fear of negative evaluation and weight/shape concerns, including the moderating roles of gender and body mass index (BMI) in adolescents. Participant were 4045 Australian adolescents (53.7% girls) aged 11–19 years (M_age = 14 years 11 months), who completed a self-report questionnaire about weight/shape concerns, fear of negative evaluation, and weight and height. Results showed a positive association between fear of negative evaluation and weight/shape concerns, with the association being stronger among girls. Furthermore, the association between fear of negative evaluation and weight/shape concerns was stronger among adolescents with higher BMIs, especially so for boys. These results highlight the role of fear of negative evaluation in weight/shape concerns and suggest potential avenues for prevention programs.