Objective: To examine gender-specific associations of weight perception and appearance satisfaction with slimming attempts and eating patterns among young Norwegian adolescents. Design: Cross-sectional study. Adolescent dietary data were reported by parents using a retrospective FFQ. Eating patterns were identified using principal component analysis. Adolescents' reported weight perception, appearance satisfaction and slimming attempts were analysed using cross-tabulation and Pearson's χ 2 test. Associations between perceived weight, appearance satisfaction and slimming attempts/eating patterns were examined using multiple logistic regression analysis. Setting: Primary schools, Telemark, Norway. Subjects: Children (n 469), mean age 12·7 (SD 0·3) years, and parents. Results: Gender differences were observed in self-perceived weight and appearance satisfaction. Girls were most satisfied with appearance when feeling thin, boys when feeling just the right weight. Perceived overweight was the main predictor of slimming attempts across genders (adjusted OR = 15·3; 95 % CI 6·0, 39·1 for girls; adjusted OR = 18·2; 95 % CI 5·8, 57·3 for boys). Low appearance satisfaction was associated with slimming attempts (adjusted OR = 3·3; 95 % CI 1·0, 10·5) and a dieting eating pattern (adjusted OR = 2·8; 95 % CI 1·5, 5·2) in girls. Perceived underweight was associated with a junk/convenience eating pattern in boys (adjusted OR = 2·8; 95 % CI 1·2, 6·4). Conclusions: Gender differences were observed in subjective body concerns. Perceived overweight was the main predictor of slimming attempts by both genders. Different aspects of body dissatisfaction were related to different food behaviours in boys and girls. Health professionals should be aware of these gender differences when planning health promotion programmes targeting young adolescents.